Methods of determining interferon having direct inhibitory effects on tumors and uses thereof

ABSTRACT

The invention provides novel methods of determining or comparing potency of a test interferon relative to rSIFN-co (an interferon having therapeutic effects on solid tumors); methods of establishing substantial equivalence between a test interferon and rSIFN-co; as well as methods for determining potency of a test interferon, kits for determination of such methods, and an interferon or an interferon substitute having said activities.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of International Application No.PCT/CN2016/081678, filed May 11, 2016, which claims the priority of U.S.Application No. 62/160,006, filed May 12, 2015. The entire contents anddisclosures of the preceding applications are hereby incorporated byreference into this application.

FIELD OF THE INVENTION

The invention herein relates to novel methods of determining potency ofa test interferon relative to rSIFN-co, methods of establishingsubstantial equivalence between a test interferon and rSIFN-co, methodsof inhibiting cancer cell migration, pseudopod formation,beta-catenin/TCF mediated transcriptional activity, and beta-cateninprotein level, methods of down-regulating expression of Wnt-relatedreceptors or co-receptors, methods of inhibiting expression of targetgenes of the Wnt signaling pathway, methods of up-regulating tumorsuppressor genes, as well as assay kits for performance of any and allsuch methods. The invention also relates to interferons or interferonsubstitutes having said activities.

BACKGROUND OF THE INVENTION

Super Interferon (hereafter, “rSIFN-co” or “SIFN-I”, an interferonhaving the therapeutic effect on solid tumors) has been described inU.S. Pat. No. 7,364,724 (Recombinant Super-Compound Interferon) and U.S.Pat. No. 7,585,647 (Nucleic Acid Encoding Recombinant Interferon).rSIFN-co is expressed from an engineered gene construct that encodes thesame amino acid sequence as INFERGEN® (interferon alfacon-1), aconsensus interferon alpha that was disclosed in U.S. Pat. No.4,695,623. However, rSIFN-co is encoded by a novel nucleic acid sequencedifferent from that encoding INFERGEN®. As compared to INFERGEN®, therSIFN-co protein has a novel tertiary structure and has improvedbiological properties as well.

rSIFN-co also has a broader spectrum of biological activities ascompared to INFERGEN®, including direct inhibitory effects on solidtumors as well as anti-viral activities, as described in U.S. Pat. Nos.8,114,395, 8,287,852, and 8,425,896.

SUMMARY OF THE INVENTION

In view of the unique biological activities of rSIFN-co compared withother interferons that are currently commercially available and thepotential of rSIFN-co for human use, it is desirable to provide formethods to assess the biological activity and/or potency of rSIFN-co andother test interferons, for example, for quality control purposes duringthe manufacturing process or otherwise, to ensure that the final productretains or has the desired activities and is different from thecurrently commercially available interferons. It is also desirable toprovide further uses of rSIFN-co and interferons or interferonsubstitutes having the desired activities.

In one aspect, the present invention provides a method of determining orcomparing potency of a test interferon relative to rSIFN-co or arSIFN-co substitute comprising: (1) providing the test interferon andrSIFN-co or rSIFN-co substitute; and (2) determining any one or more ofthe following activities on the test interferon and rSIFN-co or rSIFN-cosubstitute under same specified conditions, respectively: (a) Inhibitionof in vivo cancer cell growth in any one or more tumor-bearing animalmodels; (b) Reduction in cancer cell viability; (c) Inhibition of cancercell migration; (d) Inhibition of beta-catenin/TCF transcriptionalactivity in cancer cells; (e) Down-regulation of expression of LRP6and/or FZD6 in cancer cells; (f) Inhibition of expression of any one ormore of: Axin2, CD24, Survivin, and ID2 in cancer cells; (g) Inhibitionof pseudopod formation in cancer cells; (h) Inhibition of beta-cateninexpression in cancer cells; (i) Up-regulation of expression of any oneor more of: DKK-3, KLF-4, and BATF2 in cancer cells, such as in A549cells or SW620 cells; (j) Higher affinity binding to IFNAR1 and/or loweraffinity binding to IFNAR2 as compared to IFNα-2b; and (k) Lowersusceptibility to inhibition by B18R than IFNα-2b in up-regulation ofexpression of p-STAT in cancer cells; whereby the presence in the testinterferon of any 1, or 2, or 3, or 4, or 5, or 6 of the activitiesspecified in (a), (b), (c), (d), (e), and (f), in a statisticallysignificant manner, and/or the presence in the test interferon of anyone or more, such as 2, or 3, or 4, or 5, of the activities specified in(g), (h), (i), (j), and (k), signifies that the test interferon andrSIFN-co or rSIFN-co substitute have substantially the same potency,that is, they have substantially the same effectiveness or can generatesubstantially the same result. For purposes herein, “substantially thesame” means at least about 70% the same; optionally, at least about 80%the same; still optionally, at least about 90% the same; furtheroptionally, at least about 95% the same.

In another aspect, the present invention provides a method ofestablishing substantial equivalence between a test interferon andrSIFN-co or a rSIFN-co substitute comprising: (1) providing the testinterferon and rSIFN-co or rSIFN-co substitute; and (2) determining anyone or more of the following activities on the test interferon andrSIFN-co or rSIFN-co substitute under same specified conditions,respectively: (a) Inhibition of in vivo cancer cell growth in any one ormore tumor-bearing animal models; (b) Reduction in cancer cellviability; (c) Inhibition of cancer cell migration; (d) Inhibition ofbeta-catenin/TCF transcriptional activity in cancer cells; (e)Down-regulation of expression of LRP6 and/or FZD6 in cancer cells; (f)Inhibition of expression of any one or more of: Axin2, CD24, Survivinand ID2 in cancer cells; (g) Inhibition of pseudopod formation in cancercells; (h) Inhibition of beta-catenin expression in cancer cells; (i)Up-regulation of expression of any one or more of: DKK-3, KLF-4, andBATF2 in cancer cells, such as in A549 cells or SW620 cells; (j) Higheraffinity binding to IFNAR1 and/or lower affinity binding to IFNAR2 ascompared to IFNα-2b; and (k) Lower susceptibility to inhibition by B18Rthan IFNα-2b in up-regulation of expression of p-STAT in cancer cells;whereby the presence in the test interferon of any 1, or 2, or 3, or 4,or 5, or 6 of the activities specified in (a), (b), (c), (d), (e), and(f), in a statistically significant manner, and/or the presence in thetest interferon of any one or more, such as 2, or 3, or 4, or 5, of theactivities specified in (g), (h), (i), (j), and (k), signifies that thetest interferon and rSIFN-co or rSIFN-co substitute are substantialequivalence.

In some embodiments, the cancer cells employed in determining one ormore activities comprise any one or more of: lung cancer cells, coloncancer cells, cervical cancer cells, liver cancer cells, breast cancercells, and pancreatic cancer cells. In some embodiments, the cancercells employed in determining one or more activities comprise any one ormore of: A549 cells, Hela cells, CL-1 cells, Huh-7 cells, SW480 cells,MDA-MB-231 cells, Calu-1 cells, SMMC-7721 cells, PANC-1 cells, SW620cells, SPC-A4 cells, H1299 cells, H460 cells, and HT-29 cells.

In some embodiments, the cancer cells employed in determining activity(a), inhibition of in vivo cancer cell growth, comprise any one or moreof: liver cancer cells, cervical cancer cells, colon cancer cells, andlung cancer cells. In some embodiments, the cancer cells employed indetermining activity (a) comprise any one or more of: SMMC-7721 cells,Hela cells, HT-29 cells, SPC-A4 cells, and A549 cells; optionally,comprise any one or more of: HT-29 cells, SPC-A4 cells, and A549 cells;further optionally, comprise A549 cells. In some embodiments, normalsaline or PBS is used as control in determining inhibition in activity(a). In some embodiments, the test interferon and/or rSIFN-co orrSIFN-co substitute administered to a tumor-bearing animal model indetermining activity (a), is administered in a range of about 0.02 mg toabout 0.30 mg; optionally, about 0.05 mg to about 0.15 mg. In someembodiments, the test interferon and/or rSIFN-co or rSIFN-co substitute,administered to a tumor-bearing animal model in determining activity(a), is administered every other day. In some embodiments, the testinterferon and/or rSIFN-co or rSIFN-co substitute, administered to atumor-bearing animal model in determining activity (a), is administeredfor about 2 weeks to about 6 weeks; optionally, about 3 weeks to about 4weeks.

In some embodiments, in determining activity (b), reduction in cancercell viability, the test interferon and/or rSIFN-co or rSIFN-cosubstitute each causes about 50% reduction in viability of the cancercells at a concentration in a range of between about 6.25 mcg/ml andabout 25 mcg/ml; optionally, between about 10 mcg/ml and about 18mcg/ml; more optionally, between about 10 mcg/ml and about 15 mcg/ml. Insome embodiments, in determining activity (b), the test interferonand/or rSIFN-co or rSIFN-co substitute each causes reduction in cancercell viability to a substantially undetectable level at a concentrationin a range of at least about 25 mcg/ml; optionally, at least about 50mcg/ml; further optionally, at least about 75 mcg/ml; more optionally,at least about 100 mcg/ml. In some embodiments, in determining activity(b), the concentrations of the test interferon and/or rSIFN-co orrSIFN-co substitute comprise concentrations in a range of between about0.2 mcg/ml and about 100 mcg/ml. In some embodiments, in determiningactivity (b), the cancer cells are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute for at least about 1 day; optionally, atleast about 2 days. In some embodiments, the cancer cells employed indetermining activity (b) comprise any one or more of: lung cancer cells,colon cancer cells, cervical cancer cells, liver cancer cells, breastcancer cells, and pancreatic cancer cells; optionally, comprise any oneor more of: lung cancer cells, colon cancer cells, liver cancer cells,breast cancer cells, and pancreatic cancer cells. In some embodiments,the cancer cells employed in determining activity (b) comprise any oneor more of: A549 cells, Hela cells, CL-1 cells, Huh-7 cells, SW480cells, MDA-MB-231 cells, Calu-1 cells, SMMC-7721 cells, and PANC-1cells; optionally comprise any one or more of: A549 cells, CL-1 cells,Huh-7 cells, SW480 cells, MDA-MB-231 cells, Calu-1 cells, SMMC-7721cells, and PANC-1 cells.

In some embodiments, the cancer cells employed in determining activity(b) are treated by the test interferon and/or rSIFN-co or rSIFN-cosubstitute in a range of about 5 mcg/ml to about 20 mcg/ml; optionally,about 10 mcg/ml. In some embodiments, the cancer cells employed indetermining activity (b) are treated for about 1 day to about 10 days;optionally, about 1 day to about 6 days. In some embodiments, the cancercells employed in determining activity (b) comprise any one or more of:lung cancer cells and colon cancer cells. In some embodiments, thecancer cells employed in determining activity (b) comprise any one ormore of: A549 cells and SW620 cells.

In some embodiments, the cancer cells employed in determining activity(c), inhibition of cancer cell migration, comprise any one or more of:lung cancer cells, and colon cancer cells. In some embodiments, thecancer cells employed in determining activity (c) comprise any one ormore of: A549 cells, and SW620 cells. In some embodiments, theinhibition of cancer cell migration in activity (c) is determined usingTranswell method. In some embodiments, the cancer cells employed indetermining activity (c) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute in a range of about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml. In some embodiments, the cancercells employed in determining activity (c) are treated by the testinterferon and/or rSIFN-co or rSIFN-co substitute for at least about 20hours; optionally, at least about 24 hours.

In some embodiments, the cancer cells employed in determining activity(d), inhibition of beta-catenin/TCF transcriptional activity in cancercells, comprise any one or more of: lung cancer cells, and colon cancercells. In some embodiments, the cancer cells employed in determiningactivity (d) comprise any one or more of: A549 cells, H1299 cells, H460cells, HT-29 cells, and SW620 cells; optionally, comprise any one ormore of: A549 cells, H1299 cells, H460 cells, and SW620 cells. In someembodiments, the cancer cells in employed in determining activity (d)are treated by the test interferon and/or rSIFN-co or rSIFN-cosubstitute for at least about 20 hours; optionally, at least about 24hours. In some embodiments, the cancer cells employed in determiningactivity (d) are treated by the test interferon and/or rSIFN-co orrSIFN-co substitute in a range of about 5 mcg/ml to about 20 mcg/ml;optionally, about 10 mcg/ml. In some embodiments, the transcriptionalactivity of beta-catenin/TCF is determined by use of a reporter system.In some embodiments, the reporter system comprises TOPFlash or pSV40-RLplasmid.

In some embodiments, the cancer cells employed in determining activity(e), down-regulation of expression of LRP6 and/or FZD6 in cancer cells,comprise any one or more of: lung cancer cells, and colon cancer cells.In some embodiments, the cancer cells employed in determining activity(e) comprise any one or more of: A549 cells, H460 cells, SW620 cells,and HT-29 cells; optionally, comprise any one or more of: A549 cells,SW620 cells, and HT-29 cells; more optionally, comprise HT-29 cells. Insome embodiments, the cancer cells employed in determining activity (e)are treated by the test interferon and/or rSIFN-co or rSIFN-cosubstitute for at least about 20 hours; optionally, at least about 24hours. In some embodiments, the cancer cells employed in determiningactivity (e) are treated by the test interferon and/or rSIFN-co orrSIFN-co substitute in a range of about 5 mcg/ml to about 20 mcg/ml;optionally, about 10 mcg/ml. In some embodiments, in determiningactivity (e), the expression of LRP6 and/or FZD6 is determined bydetermining mRNA level of LRP6 and/or FZD6.

In some embodiments, the cancer cells employed in determining activity(f), inhibition of expression of any one or more of: Axin2, CD24,Survivin and ID2, comprise lung cancer cells; optionally, comprise A549cells. In some embodiments, the cancer cells employed in determiningactivity (f) are treated by the test interferon and/or rSIFN-co orrSIFN-co substitute for at least about 20 hours; optionally, at leastabout 24 hours. In some embodiments, the cancer cells employed indetermining activity (f) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute in a range of about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml. In some embodiments, in determiningactivity (f) the expression of Axin2, CD24, Survivin and/or ID2 isdetermined by determining its corresponding mRNA level. In someembodiments, in determining activity (f), when the test interferondecreases at least about 30%; optionally, at least about 40%; moreoptionally, at least about 50%; still more optionally, at least about60% in expression of any one or more of: Axin2, CD24, Survivin and ID2in the cancer cells as compared to control, the test interferon and/orrSIFN-co or rSIFN-co substitute are considered to have substantially thesame potency or substantial equivalence.

In some embodiments, the cancer cells employed in determining activity(g), inhibition of pseudopod formation, comprise lung cancer cells;optionally, A549 cells. In some embodiments, the cancer cells employedin determining activity (g) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute for at least about 4 days; optionally,at least about 8 days. In some embodiments, the cancer cells employed indetermining activity (g) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute in a range of about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml.

In some embodiments, the cancer cells employed in determining activity(h), inhibition of beta-catenin expression in cancer cells, comprise anyone or more of: lung cancer cells and colon cancer cells. In someembodiments, the cancer cells employed in determining activity (h)comprise any one or more of: A549 cells and SW480 cells. In someembodiments, in determining activity (h) the inhibition of beta-cateninexpression is determined by Western Blot. In some embodiments, thecancer cells employed in determining activity (h) are treated by thetest interferon and/or rSIFN-co or rSIFN-co substitute for at leastabout 48 hours; optionally, at least about 72 hours. In someembodiments, the cancer cells employed in determining activity (h) aretreated by the test interferon and/or rSIFN-co or rSIFN-co substitute ina range of about 5 mcg/ml to about 20 mcg/ml; optionally, about 10mcg/ml.

In some embodiments, the cancer cells employed in determining activity(i), up-regulation of expression of any one or more of: DKK-3, KLF-4,and BATF2 in cancer cells, comprise any one or more of: lung cancercells, and colon cancer cells. In some embodiments, the cancer cellsemployed in determining activity (i) comprise any one or more of: A549cells, H460 cells, SW620 cells, and HT-29 cells; optionally, compriseany one or more of: A549 cells, and SW620 cells. In some embodiments,the cancer cells employed in determining activity (i) are treated by thetest interferon and/or rSIFN-co or rSIFN-co substitute for at leastabout 20 hours; optionally, at least about 24 hours. In someembodiments, the cancer cells employed in determining activity (i) aretreated by the test interferon and/or rSIFN-co or rSIFN-co substitute ina range of about 5 mcg/ml to about 20 mcg/ml; optionally, about 10mcg/ml. In some embodiments, in determining activity (i) the expressionof DKK-3, KLF-4 and/or BATF2 is determined by determining itscorresponding mRNA level.

In some embodiments, in determining activity (j), when the testinterferon has at least about 2 times; optionally, at least about 3times; more optionally, at least about 4 times; still more optionally,at least about 4.5 times, such as 4.72 times, higher affinity binding toIFNAR1 as compared to IFNα-2b, the test interferon and/or rSIFN-co orrSIFN-co substitute are considered to have substantially the samepotency or substantial equivalence. In some embodiments, in determiningactivity (j), when the test interferon has at least about 5 times;optionally, at least about 7 times; more optionally, at least about 9times; still more optionally, at least about 11 times, such as 11.9times, lower affinity binding to IFNAR2 as compared to IFNα-2b, the testinterferon and/or rSIFN-co or rSIFN-co substitute are considered to havesubstantially the same potency or substantial equivalence. In someembodiments, in determining activity (j), the binding affinity ofIFNα-2b, the test interferon and/or rSIFN-co or rSIFN-co substitute toIFNAR1 and/or IFNAR2 is determined by determining its dissociationconstant (K_(D)).

In some embodiments, the cancer cells employed in determining activity(k) comprise any one or more of: A549 cells and Hela cells. In someembodiments, in determining activity (k), the IFNα-2b, the testinterferon and/or rSIFN-co or rSIFN-co substitute is incubated with B18Rin a range of about 5 ng/ml to about 20 ng/ml, optionally, about 10ng/ml, before contacting the cancer cell. In some embodiments, indetermining activity (k), when the test interferon has a lowersusceptibility to inhibition by B18R in up-regulation of expression ofp-STAT in cancer cells, as compared to IFNα-2b, the test interferonand/or rSIFN-co or rSIFN-co substitute are considered to havesubstantially the same potency or substantial equivalence. In someembodiments, in determining activity (k), the up-regulation of p-STATexpression is determined by Western Blot.

In some embodiments, statistical significance means a p value of lessthan or equal to 0.05, or less than or equal to 0.01, or less than orequal to 0.005, or less than or equal to 0.001, or less than or equal to0.0005, or less than or equal to 0.0001, when compared to a control.

In some embodiments, the control is not treated with the test interferonor rSIFN-co or rSIFN-co substitute, or is treated with normal saline orPBS, or is treated with IFNα-2b, or the control is untreated control(Mock).

In another aspect, the present invention provides a method ofdetermining or comparing the potency of a compound, such as a testinterferon, comprising: (a) providing a plurality of concentrations ofthe test interferon; (b) determining a first dose response of the testinterferon, using the plurality of concentrations of the testinterferon, on the viability of a first set of cancer cells underspecified conditions; (c) providing a plurality of concentrations ofrSIFN-co or rSIFN-co substitute; (d) determining a second dose responseof the rSIFN-co or rSIFN-co substitute, using the plurality ofconcentrations of the rSIFN-co or the rSIFN-co substitute, on viabilityof a second set of cancer cells under the same specified conditions; and(e) comparing the first dose response with the second dose response. Insuch a manner, the potency of the compound, such as the test interferon,is determined relative to rSIFN-co or rSIFN-co substitute.

In some embodiments, the rSIFN-co comprises a specified specificactivity, and the specific activity is in the range between about 4×10⁸IU/mg to about 1×10⁹ IU/mg. In some embodiments, the specific activityis in the range between about 4.4×10⁸ IU/mg to about 9×10⁸ IU/mg. Insome embodiments, the specific activity is in the range between about5×10⁸ IU/mg to about 8×10⁸ IU/mg. In some embodiments, the specificactivity is in the range between about 6×10⁸ IU/mg to about 7.5×10⁸IU/mg. Optionally, the specific activity is in the range between about4×10⁸ IU/mg to 5×10⁸ IU/mg.

In some embodiments, in the methods of determining or comparing thepotency of a compound, the concentrations of the test interferon orrSIFN-co are in a range between about 0.2 mcg/ml and about 100 mcg/ml.In some embodiments, the concentrations of the test interferon orrSIFN-co are at least two or more of the following: 0.2 mcg/ml, 0.39mcg/ml, 0.78 mcg/ml, 1.56 mcg/ml, 3.13 mcg/ml, 6.25 mcg/ml, 12.5 mcg/ml,25 mcg/ml, 50 mcg/ml, and 100 mcg/ml.

In some embodiments, the cancer cells are treated with the testinterferon or rSIFN-co for at least about 20 hr, optionally, at leastabout 24 hr, still optionally, at least about 48 hr, and moreoptionally, at least about 72 hr.

In some embodiments, the invention provides the methods as describedherein, wherein the rSIFN-co has a potency of being able to reduceviability of the cancer cells by 50% at a concentration in the range ofbetween about 6.25 mcg/ml and about 25 mcg/ml, depending on the cancercell type. In some embodiments, the rSIFN-co is capable of reducingviability of the cells by 50% at a concentration in the range of betweenabout 6.25 mcg/ml and 12.5 mcg/ml. In another embodiment, the rSIFN-cois capable of reducing viability of the cells by 50% at a concentrationin the range of between about 12.5 mcg/ml and 25 mcg/ml. In someembodiments, the IC₅₀ of the rSIFN-co is in the range of about 10 mcg/mlto about 18 mcg/ml, optionally, about 10 mcg/ml to about 15 mcg/ml.

In another aspect, the present invention provides a method ofdetermining or comparing potency of a compound, such as a testinterferon, relative to rSIFN-co or rSIFN-co substitute, on viability ofcancer cells, comprising: (a) providing a plurality of cancer cells; (b)testing a first set of the cancer cells with an amount of the testinterferon under specified conditions to generate a first set ofviability data; (c) treating a second set of the cancer cells with aneffective amount of rSIFN-co or rSIFN-co substitute under the samespecified conditions to generate a second set of viability data; and (d)comparing the first set of viability data with the second set ofviability data, whereby the potency of the test interferon isdetermined.

In some embodiments, the cancer cells are treated for a range from about1 day to about 6 days. In some embodiments, the rSIFN-co is used at aconcentration in the range of about 6.25 mcg/ml to about 50 mcg/ml;optionally, about 7 mcg/ml to about 25 mcg/ml; further optionally, about8 mcg/ml to about 12.5 mcg/ml; still optionally, about 10 mcg/ml. Insome embodiments, the rSIFN-co is used at a concentration in the rangeof about 5 mcg/ml to about 20 mcg/ml. In some embodiments, the rSIFN-cocomprises a specified specific activity.

In some embodiments, the cancer cells used herein are chosen from amonghuman tumor cells and animal tumor cells. In some embodiments, the tumorcells are lung tumor cells, or cervical tumor cells, or liver tumorcells, or colon tumor cells, or breast tumor cells, or pancreatic tumorcells, or prostate tumor cells, or viral-induced tumor cells or virallytransformed cells. In some embodiments, the cancer cells are chosen fromat least one of: A549 cells, SPC-A4 cells, Calu-1 cells, CL-1 cells,H460 cells, H1299 cells, Hela cells, HT-29 cells, Huh-7 cells,MDA-MB-231 cells, PANC-1 cells, RAW264.7 cells, SMMC-7721 cells, SW480cells, and SW620 cells.

In some embodiments, the test interferon is also an interferon,including an interferon obtained from a different manufacturing lot thanthe rSIFN-co. In some embodiments, the amino acid sequence of the testinterferon is at least 90%, optionally, at least 95%, 96%, 97%, 98%,99%, 100% identical to that of rSIFN-co (SEQ ID NO: 1). In someembodiments, the nucleotide sequence encoding the test interferon is atleast 90%, optionally, at least 95%, 96%, 97%, 98%, 99%, 100% identicalto that encoding rSIFN-co (SEQ ID NO: 2). In some embodiments, the testinterferon and rSIFN-co have same amino acid sequence (SEQ ID NO: 1) andare encoding by same nucleotide sequence (SEQ ID NO: 2). In someembodiments, the test interferon and rSIFN-co have substantially thesame specific activity. In some embodiments, the specific activity is inthe range between about 4×10⁸ IU/mg to about 1×10⁹ IU/mg. In someembodiments, the test interferon is obtainable by a process comprisingintroducing into E. coli the polynucleotide sequence shown in SEQ IDNO:2. In some embodiments, the test interferon is made by expression ofthe polynucleotide (SEQ ID NO:2) in a E. coli host, optionally under thecontrol of promoter P_(BAD) in a E. coli host.

In another aspect, the present invention provides a method of inhibitingcell migration, such as that occurring in tumor metastases, comprisingexposing the cells to an effective amount of rSIFN-co for a specifiedperiod of time, whereby cell migration is inhibited.

In some embodiments, the effective amount of the rSIFN-co comprisesabout 5 mcg/ml to about 100 mcg/ml; optionally, about 8 mcg/ml to about50 mcg/ml; still optionally, about 10 mcg/ml to about 25 mcg/ml; furtheroptionally, about 12 mcg/ml to about 18 mcg/ml. In some embodiments, theeffective amount of the rSIFN-co comprises about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml.

In another aspect, the invention provides a method of inhibitingpseudopod formation in cancer cells, comprising exposing the cancercells to an effective amount of rSIFN-co, for a specified period oftime, whereby pseudopod formation is inhibited. In some embodiments, theeffective amount of the rSIFN-co comprises about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml.

In a further aspect, the invention provides a method of inhibitingbeta-catenin/TCF-mediated transcriptional activity in cells, comprisingexposing the cells to an effective amount of rSIFN-co for a specifiedperiod of time. In some embodiments, the beta-catenin/TCF-mediatedtranscriptional activity is determined using a reporter system,optionally, a luciferase reporter system. In some embodiments, thereporter system is TOPFlash reporter. In some embodiments, the plasmidpSV40-RL is used.

In another aspect, the invention additionally provides a method ofdecreasing beta-catenin protein level in cells comprising exposing cellsto an effective amount of rSIFN-co for a specified period of time. Insome embodiments, the protein level of beta-catenin is detected byWestern Blot using its specific antibody. In some embodiments, GAPDH isused as a control.

In another aspect, the invention provides a method for down-regulatingexpression of a Wnt-related receptor or co-receptor in cells, comprisingexposing the cells to an effective amount of rSIFN-co for a specifiedtime, whereby the Wnt-related receptor or co-receptor is down-regulated.In some embodiments, the Wnt-related receptor or co-receptor comprises aLRP protein, such as LRP6. In some embodiments, the Wnt-signalingreceptor or co-receptor comprises a FZD protein, such as FZD6. In someembodiments, determining the expression of the Wnt-related receptor orco-receptor comprises determining the mRNA level of such receptor orco-receptor. In some embodiments, cDNA corresponding to such mRNA ismade to determine such mRNA levels.

In a further aspect, the invention provides a method of inhibiting theexpression of certain genes in cells, including at least one target geneof the Wnt-signaling pathway, such as for treatment of a disease orcondition in which the target gene is over-active. Such down-regulatedgenes include Axin2, CD24, Survivin, and/or ID2. The method comprisesexposing the cells to an effective amount of rSIFN-co for a specifiedperiod of time, whereby expression of the target gene is inhibited.

In some embodiments of the invention, the specified period of time forexposure of cells to rSIFN-co is at least about 12 hr; optionally, atleast about 20 hr; further optionally, at least about 24 hr; moreoptionally, for at least about 36 hr; still optionally, at least forabout 48 hr; yet still optionally, at least about 72 hr. In someembodiments, the cells being treated by rSIFN-co are cancer cells.

In a further aspect, the invention provides a method of up-regulatingexpression of certain genes in cells, including at least one tumorsuppressor gene, comprising exposing the cells to an effective amount ofrSIFN-co for a specified period of time, whereby up-regulation ofexpression at least one tumor suppressor gene is effected. In someembodiments, the up-regulated gene comprises at least one of DKK3, KLF4,and BATF2. In some embodiments, the expression of the up-regulated geneis determined by measuring such mRNA level. In some embodiments, cDNA issynthesized from such mRNA and is optionally amplified for suchmeasurement purposes.

In another aspect, the invention provides a method of establishingsubstantial equivalence between a test compound and rSIFN-co or rSIFN-cosubstitute in at least one, optionally at least 2, 3, 4, 5, 6, 7, 8, 9,10 or 11 of the following, comprising comparing the activities theretoand showing substantially the same responses: (a) Inhibition of in vivocancer cell growth in any one or more tumor-bearing animal models; (b)Reduction in cancer cell viability; (c) Inhibition of cancer cellmigration; (d) Inhibition of beta-catenin/TCF transcriptional activityin cancer cells; (e) Down-regulation of expression of LRP6 and/or FZD6in cancer cells; (f) Inhibition of expression of any one or more of:Axin2, CD24, Survivin and ID2 in cancer cells; (g) Inhibition ofpseudopod formation in cancer cells; (h) Inhibition of beta-cateninexpression in cancer cells; (i) Up-regulation of expression of any oneor more of: DKK-3, KLF-4, and BATF2 in cancer cells; (j) Higher affinitybinding to IFNAR1 and/or lower affinity binding to IFNAR2 as compared toIFNα-2b; and (k) Lower susceptibility to inhibition by B18R than IFNα-2bin up-regulation of p-STAT in cancer cells. In some embodiments, theinvention provides establishing substantial equivalence in at least 2 ofthe fore-mentioned activities; optionally the invention providesestablishing substantial equivalence in at least 3 of the fore-mentionedactivities; optionally, in at least 4 of the fore-mentioned activities;still optionally, in at least 5 of the fore-mentioned activities;further optionally, in at least 6 of the fore-mentioned activities;still further optionally, in at least 7, or 8, or 9, or 10, or 11 of thefore-mentioned activities.

In another aspect, the present invention provides assay kits forassessing potency of a test interferon, for inhibiting expression of atleast one Wnt-related target gene, for up-regulation of a tumorsuppressor gene, and/or for down-regulating expression of LRP6 and/orFZD6, comprising (a) rSIFN-co or rSIFN-co substitute and (b) at leastone of: instructions for performing one or more of the methods describedherein and reagents for performing such methods. The reagent may includePhosphate Buffered Saline (PBS) or a buffer. In some embodiments, therSIFN-co or rSIFN-co substitute in the assay kit comprises a specifiedspecific activity.

In another aspect, the present invention provides an interferon or aninterferon substitute, comprising any one or more activities, optionally2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 activities selected from: inhibitionof in vivo cancer cell growth in any one or more tumor-bearing animalmodels; reduction in cancer cell viability; inhibition of cancer cellmigration; inhibition of beta-catenin/TCF transcriptional activity incancer cells; down-regulation of expression of LRP6 and/or FZD6 incancer cells; inhibition of expression of any one or more of: Axin2,CD24, Survivin and ID2 in cancer cells; inhibition of pseudopodformation in cancer cells; inhibition of beta-catenin expression incancer cells; up-regulation of expression of any one or more of: DKK-3,KLF-4, and BATF2 in cancer cells; higher affinity binding to IFNAR1and/or lower affinity binding to IFNAR2 as compared to IFNα-2b; andlower susceptibility to inhibition by B18R than IFNα-2b in up-regulationof expression of p-STAT in cancer cells; wherein said interferon orinterferon substitute is not rSIFN-co.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the growth curves of human hepatoma tumors, SMMC-7721, innude mice, as described in Example 1, as represented by mean relativetumor volume (RTV), for each of the groups treated with either MMC (at 5mg/kg) or rSIFN-co at 0.15 mg/mouse, 0.10 mg/mouse or 0.05 mg/mouse, orwas injected with vehicle, normal saline (NS) (0.15 ml/mouse), over the21-day period after the start of treatment.

FIG. 2 shows the growth curves of human cervical tumor in nude mice, asdescribed in Example 2, as represented by RTV, for each of the groupstreated with either MMC (at 5 mg/kg) or rSIFN-co at 0.15 mg/mouse, 0.10mg/mouse, or 0.05 mg/mouse, or was injected with vehicle, normal saline(0.15 ml per mouse), over the 28-day treatment period.

FIG. 3 shows the growth curves of human colon tumor, HT-29, in nudemice, as described in Example 3, as represented by RTV for each of thegroups treated with either MMC (at 5 mg/kg) or rSIFN-co at 0.15mg/mouse, 0.10 mg/mouse, or 0.05 mg/mouse, or IFNalpha-2b at 0.15mg/mouse, or was injected with vehicle, normal saline (0.15 ml permouse), over the 28-day treatment period.

FIG. 4 shows the growth curves of human lung tumor, SPC-A4, in nudemice, as described in Example 4, as represented by RTV for each of thegroups treated with either MMC (at 5 mg/kg) or rSIFN-co at 0.15mg/mouse, 0.10 mg/mouse, or 0.05 mg/mouse, or IFNalpha-2b at 0.15mg/mouse, or was injected with vehicle, normal saline (0.15 ml permouse), over the 21-day treatment period.

FIG. 5 shows dose response curves on the viability of different tumorcells after treatment for 48 hr with either rSIFN-co or IFN alpha-2b(IFNα-2b) at the concentrations indicated in mcg/ml (g/ml): 0, 0.2,0.39, 0.78, 1.56, 3.13, 6.25, 12.50, 25, 50, and 100. The cells testedwere: A549 lung tumor cells (FIG. 5A); Hela cervical tumor cells (FIG.5B); CL-1 liver tumor cells (FIG. 5C); Huh-7 liver tumor cells (FIG.5D); SW480 colon tumor cells (FIG. 5E); MDA-MB-231 breast tumor cells(FIG. 5F); Calu-1 lung tumor cells (FIG. 5G); SMMC-7721 liver tumorcells (FIG. 5H); and PANC-1 pancreatic tumor cells (FIG. 5I). Resultsare expressed as a percentage of cell viability relative to controlcells, and represent the mean of at least two independent experiments.

FIG. 6 are viability curves showing the effect of IFN alpha-2b treatmentand rSIFN-co treatment, respectively, at 10 mcg/ml, on the viability ofA549 cells (FIG. 6A) and SW620 (FIG. 6B) cells after treatment for theindicated number of days: 1, 2, 3, 4, 5, and 6. Cell viability wasevaluated by the MTT assay. Results are expressed as percentage cellviability relative to control cells and represent the mean of at least 2independent experiments. (**p<0.01)

FIG. 7 are photomicrographs showing the effect of rSIFN-co treatment(FIG. 7, column C) and IFN alpha-2b treatment (FIG. 7, column B),respectively, as compared to Mock control (FIG. 7, column A) on lungcancer cells, A549, on colony formation after 4 days (row 1) (magnified100×) and invasive feet (pseudopods) formation after 8 days (rows 2 and3)(magnified 400×), in 3D culture. Black arrows in columns A and B pointto pseudopods protruding from the cancer cells. Arrows with a star incolumn C point to cells without pseudopod.

FIG. 8, A-E are bar diagrams showing the effect of rSIFN-co treatmentand IFN alpha-2b treatment, respectively, on beta-catenin/TCF-mediatedtranscriptional activity in different lung cancer cells: A549 (FIG. 8A);H1299 (FIG. 8B); and H460 (FIG. 8C); and different colon cancer cells:HT-29 (FIG. 8D); and SW620 (FIG. 8E) as compared to mock control. Valueswere averages of 3 experiments. (*p<0.05, **p<0.01).

FIGS. 9, A and B, are bar diagrams showing the effect of rSIFN-cotreatment and IFN alpha-2b treatment, respectively, as compared to mockcontrol on the expression of Wnt-related receptors or co-receptors, LRP6(FIG. 9A) and FZD6 (FIG. 9b ) in different cancer cells as measured bymRNA levels relative to expression of GAPDH: A549, H460, SW620, andHT-29. Experiment was conducted in triplicate and results werenormalized with the mock control group.

FIGS. 10, A and B, are Western Blots and showing the effect of rSIFN-cotreatment and IFN alpha-2b treatment, respectively, as compared to mockcontrol, on beta-catenin protein level in cancer cells: A549 (FIG. 10A)and SW480 (FIG. 10B), after 24, 48 and 72 hr of treatment, respectively.GAPDH expression was used as a control. Experiment was conducted intriplicate.

FIG. 11, A-D, are bar diagrams showing the relative mRNA expressionlevel of four (4) genes that are downstream of the Wnt-signaling pathwayafter A549 lung cancer cells were treated for twenty-four (24) hourswith either rSIFN-co or IFN alpha-2b, as compared to mock control: Axin2(FIG. 11A); CD24 (FIG. 11B); Survivin (FIG. 11C); and ID2 (FIG. 11D).Experiment was conducted in triplicate and normalized with the mockcontrol group.

FIG. 12, A-C, are bar diagrams showing the relative mRNA expressionlevel of 3 tumor suppressor genes: DKK-3 (FIG. 12A); BATF2 (FIG. 12B);and KLF4 (FIG. 12C) in different tumor cells: A549, H460, SW620, andHT-29, that were treated with either rSIFN-co or IFN alpha-2b, ascompared to mock control. Experiment was conducted in triplicate andnormalized with the mock control group.

FIGS. 13, A and B, are bar diagrams showing the tumor cell migrationafter treatment with either IFN alpha-2b or rSIFN-co as compared to Mockcontrols, for A549 cells (FIG. 13A) and SW620 cells (FIG. 13B). Resultsare presented as the mean number of migrating cells per field±SD aftersuch treatment. (**p<0.01)

FIG. 14 are Western Blots, stained with specific antibodies toprocaspase-3, cleaved caspase-3, procaspase-8, cleaved caspase-8, PARP,and beta-tubulin (β-tubulin), from A549 cells (FIG. 14A) and SW620 cells(FIG. 14B) after they were treated with either IFN alpha-2b or rSIFN-cofor 24 hr or 48 hr as compared to Mock controls and 5FU-treated cells,respectively.

FIG. 15 are Western Blots, stained with specific antibodies to P-STAT1,STAT1, P-STAT2, STAT2, P-STAT3, STAT3 and GAPDH, after A549 cells weretreated with IFN alpha-2b (FIG. 15A) at 10 mcg/ml, or rSIFN-co (FIG.15B) at 10 mcg/ml, or after Hela cells were treated with IFN alpha-2b(FIG. 15C) at 10 mcg/ml, or rSIFN-co (FIG. 15D) at 10 mcg/ml.

FIG. 16 is a tumor growth curve showing the inhibition of tumor growthafter treatment by either IFN alpha-2b or rSIFN-co as compared toPBS-treated controls over a period of 27 days after initiation oftreatment. Data are presented as mean tumor volume (mm³)±SD (n=8).

FIG. 17A shows the affinity constant of IFNAR1 interferon receptor asanalyzed by steady-analysis model: K_(D) (IFNAR1-EC/IFNα-2b): 2.835×10⁻⁶mol/L (black diamond) and K_(D)(IFNAR1-EC/rSIFN-co): 6.003×10⁻⁷ mol/L(black circle). FIG. 17B shows the affinity constant of IFNAR2interferon receptor as analyzed by dynamic-analysis model:K_(D)(IFNAR2-EC/IFNα-2b) 1.843×10⁻⁹ mol/L and K_(D)(IFNAR2-EC/rSIFN-co): 2.192×10⁻⁸ mol/L. FIG. 17C are bar diagramsshowing the comparison of receptor binding affinity of IFNα-2b andrSIFN-co to IFNAR1-EC or IFNAR2-EC, respectively, indicating thatrSIFN-co/IFNAR1 exhibits a stronger binding affinity that is about 4.72times stronger than that of IFNα-2b/IFNAR1, and rSIFN-co/IFNAR2 exhibitsa weaker binding affinity that is about 11.9 times weaker than that ofIFNα-2b/IFNAR2.

FIG. 18 are Western Blots, stained with specific antibodies to P-STAT1,STAT1, P-STAT2, STAT2, P-STAT3, STAT3, Actin and GAPDH, after cancercells were treated with either rSIFN-co or IFNα-2b, each at 1 ng/ml(final assay concentration), that was previously incubated with B18Rrecombinant protein at 1, 10 or 100 ng/ml, respectively, where thecancer cells were A549 cells (FIG. 18A), or Hela cells (FIG. 18B).

DETAILED DESCRIPTION OF THE INVENTION Definitions

Unless otherwise indicated, scientific and technical terms used hereinshall have the meanings given them by those of ordinary skill in the artor that are commonly understood by those of ordinary skill in the art.

Further, unless otherwise required by context, singular terms shallinclude pluralities and plural terms shall include the singular.

In addition, as used herein, the term “or” shall mean “and/or” unlessotherwise stated.

As used herein, the term “compound” shall mean any protein (includingany antibody, any active antibody fragment, and any dimeric ormultimeric protein), polypeptide, small molecule, and other moleculeshaving one or more biological activities.

The term “comprise” or “comprising” as used herein shall be readexpansively and without limitation, and shall include “is” or “are.”

The term “condition” and “disease” as used herein may be usedinterchangeably or together to indicate an illness, infection,inflammation, cancer, a side effect caused by treatment, or other causesof poor health in a subject.

The term “effective amount” as used herein shall mean an amount thatproduces the desired effect, such as for reduction of cell viability,down-regulation or up-regulation of expression or activity of a protein,or treatment of a disease or condition.

The term “establishing substantial equivalence” as used herein shallmean conducting certain test or tests to demonstrate substantially thesame level of response, activity, effectiveness or result, within thelimits of experimental error (such as ±standard deviation (SD)).

The term “substantially the same” as used herein shall mean at leastabout 70% the same; optionally, at least about 80% the same; stilloptionally, at least about 90% the same; further optionally, at leastabout 95% the same.

The terms “in the range of about” or “in the range between about” asused herein shall mean the number specified in the range plus all unitsand decimal points in-between such specified range. For example, “in therange between about 4×10⁸ IU/mg to about 5×10⁸ IU/mg” shall include4×10⁸ IU/mg, 4.1×10⁸ IU/mg, 4.2×10⁸ IU/mg, 4.3×10⁸ IU/mg, 4.4×10⁸ IU/mg,and the like, and “8 mcg/ml to 20 mcg/ml” shall include 9 mcg/ml, 10mcg/ml and the like.

The term “include” or “including” as used herein shall be construed asnon-limiting and embodies the elements specified as well asnon-specified elements.

The term “interferon” or “IFN” as used herein shall mean any naturallyoccurring or artificially created interferon, including consensusinterferon alpha, as described in U.S. Pat. No. 4,695,623, entitled“Consensus human leukocyte interferon,” as well as rSIFN-co.

The term “interferon activity” as used herein shall mean one or morebiological activities that characterize a naturally occurring interferonand rSIFN-co, such as, for example, anti-tumor activity and/oranti-viral activity.

The term “rSIFN-co” as used herein shall mean the protein or nucleicacid molecule, as the context requires, having the polynucleotidesequence and amino acid sequence as described in U.S. Pat. Nos.7,364,724, 7,585,647, or an active fragment of such. Said polynucleotidesequence and amino acid sequence as described in U.S. Pat. No.7,364,724,

M   C  D   L  P  Q  T   H  S  L   G  N  R   R  A  L  I   L  L  A   1ATGTGCGACC TGCCGCAGAC CCACTCCCTG GGTAACCGTC GTGCTCTGAT CCTGCTGGCTTACACGCTGG ACGGCGTCTG GGTGAGGGAC CCATTGGCAG CACGAGACTA GGACGACCGAQ   M  R   R  I  S  P   F  S  C   L  K  D   R  H  D  F   G  F  P  61CAGATGCGTC GTATCTCCCC GTTCTCCTGC CTGAAAGACC GTCACGACTT CGGTTTCCCGGTCTACGCAG CATAGAGGGG CAAGAGGACG GACTTTCTGG CAGTGCTGAA GCCAAAGGGCQ   E  E   F  D  G  N   Q  F  Q   K  A  Q   A  I  S  V   L  H  E 121CAGGAAGAAT TCGACGGTAA CCAGTTCCAG AAAGCTCAGG CTATCTCCGT TCTGCACGAAGTCCTTCTTA AGCTGCCATT GGTCAAGGTC TTTCGAGTCC GATAGAGGCA AGACGTGCTTM   I  Q   Q  T  F  N   L  F  S   T  K  D   S  S  A  A   W  D  E 181ATGATCCAGC AGACCTTCAA CCTGTTCTCC ACCAAAGACT CCTCCGCTGC TTGGGACGAATACTAGGTCG TCTGGAAGTT GGACAAGAGG TGGTTTCTGA GGAGGCGACG AACCCTGCTTS   L  L   E  K  F  Y   T  E  L   Y  Q  Q   L  N  D  L   E  A  C 241TCCCTGCTGG AAAAATTCTA CACCGAACTG TACCAGCAGC TGAACGACCT GGAAGCTTGCAGGGACGACC TTTTTAAGAT GTGGCTTGAC ATGGTCGTCG ACTTGCTGGA CCTTCGAACGV   I  Q   E  V  G  V   E  E  T   P  L  M   N  V  D  S   I  L  A 301GTTATCCAGG AAGTTGGTGT TGAAGAAACC CCGCTGATGA ACGTTGACTC CATCCTGGCTCAATAGGTCC TTCAACCACA ACTTCTTTGG GGCGACTACT TGCAACTGAG GTAGGACCGAV   K  K   Y  F  Q  R   I  T  L   Y  L  T   E  K  K  Y   S  P  C 361GTTAAAAAAT ACTTCCAGCG TATCACCCTG TACCTGACCG AAAAAAAATA CTCCCCGTGCCAATTTTTTA TGAAGGTCGC ATAGTGGGAC ATGGACTGGC TTTTTTTTAT GAGGGGCACGA   W  E   V  V  R  A   E  M  R   S  S  F   S  L  S  T   N  L  Q 421GCTTGGGAAG TTGTTCGTGC TGAAATCATG CGTTCCTTCT CCCTGTCCAC CAACCTGCAGCGAACCCTTC AACAAGCACG ACTTTAGTAC GCAAGGAAGA GGGACAGGTG GTTGGACGTCE   R  L   R  R  K  E (SEQ ID NO: 1) 481 GAACGTCTGC GTCGTAAAGA ATAA(SEQ ID NO: 2) CTTGCAGACG CAGCATTTCT TATT (SEQ ID NO: 3)

The term “rSIFN-co substitute,” as used herein shall mean any compound,the potency of which has been or will be measured against rSIFN-co andcan be used in place of rSIFN-co for comparative purposes in thedetermination of potency or activity of a test compound. The rSIFN-cosubstitute may be an interferon or a compound having interferonproperties.

As used herein, specific activity is the ratio of the biologicalactivity and the content of protein. The biological activity can be anyrelevant biological activity as conventional in the art, such as thebiological activity measured by cell lesion inhibition method publishedin Appendix X C in Chinese Pharmacopoeia (the 3^(rd) book), 2010edition. The protein content can be measured by any method conventionalin the art, such as the Lowry method, published in Appendix VI B inChinese Pharmacopoeia (the 3^(rd) book), 2010 edition.

The term “treatment” as used herein shall include causing a complete orpartial cure of a disease, arresting or inducing non-progression of adisease, ameliorating or reducing the severity of a disease or symptoms,preventing the recurrence of a disease, reducing the frequency ofrecurrence of a disease, reducing side effects of a disease, placing adisease in remission, causing a general feeling of improved health andthe like.

The term “Wnt-related receptor or co-receptor” shall include one or moremolecules that individually or together binds to a Wnt family protein toinitiate signaling in the canonical Wnt signaling pathway ornon-canonical Wnt signaling pathway in cells. This term includes, forexample, LRP6, a low density lipoprotein receptor-related protein 6,which is known to interact with DKK1, a Wnt-coreceptor and FZD6, areceptor for Wnt signaling and believed to be a receptor for Wnt-4ligand.

The term “Wnt signaling activity” as used herein refers to the Wntsignaling cascade transduced through binding to Frizzled (FZD) familyreceptors and LRP5/LRP6 co-receptor, leading to the release ofbeta-catenin and its migration into the nucleus for cell activation.

The term “IFNAR1” as used herein refers to the 557 amino acid receptorprotein cloned by Uze et al, Cell, 60: 225-234 (1990), including anextracellular domain of 409 residues, a transmembrane domain of 21residues, and an intracellular domain of 100 residues, as shown in FIG.5 on page 229 of Uze et al. In some embodiments, the foregoing terminclude fragments of IFNAR1 that contain the extracellular domain (EC orECD) (or fragments of the EC or ECD) of IFNAR1.

The term “IFNAR2” as used herein refers to the 515 amino acid receptorprotein cloned by Domanski et al., J. Biol. Chem., 37: 21606-21611(1995), including an extracellular domain of 217 residues, atransmembrane domain of 21 residues, and an intracellular domain of 250residues, as shown in FIG. 1 on page 21608 of Domanski et al. In someembodiments, the foregoing term include fragments of IFNAR2 that containthe extracellular domain (EC or ECD) (or fragments of the EC or ECD) ofIFNAR2.

The inventors herein discovered certain biological effects resultingfrom administration or treatment of rSIFN-co and that these biologicaleffects can be employed to assess the potency of rSIFN-co and othercompounds that may have similar properties, especially during themanufacturing process when consistency in potency is desired or in drugdevelopment process when improvement in potency is sought. The inventorshave further discovered certain biological effects upon treatment withrSIFN-co, heretofore unknown, and that such biological effects may beemployed for further uses of rSIFN-co, including for the treatment ofother conditions or diseases where up-regulation or down-regulation ofcertain genes is desirable.

In one aspect, the present invention provides a method of determining orcomparing potency of a test interferon relative to rSIFN-co or arSIFN-co substitute comprising: (1) providing the test interferon andrSIFN-co or rSIFN-co substitute; and (2) determining any one or more ofthe following activities of the test interferon and rSIFN-co or rSIFN-cosubstitute under same specified conditions, respectively: (a) Inhibitionof in vivo cancer cell growth in any one or more tumor-bearing animalmodels; (b) Reduction in cancer cell viability; (c) Inhibition of cancercell migration; (d) Inhibition of beta-catenin/TCF transcriptionalactivity in cancer cells; (e) Down-regulation of expression of LRP6and/or FZD6 in cancer cells; (f) Inhibition of expression of any one ormore of: Axin2, CD24, Survivin and ID2 in cancer cells; (g) Inhibitionof pseudopod formation in cancer cells; (h) Inhibition of beta-cateninexpression in cancer cells; (i) Up-regulation of expression of any oneor more of: DKK-3, KLF-4, and BATF2 in cancer cells, such as in A549cells or SW620 cells; (j) Higher affinity binding to IFNAR1 and/or loweraffinity binding to IFNAR2 as compared to IFNα-2b; and (k) Lowersusceptibility to inhibition by B18R than IFNα-2b in up-regulation ofexpression of p-STAT in cancer cells; whereby the presence in the testinterferon of any 1, or 2, or 3, or 4, or 5, or 6 of the activitiesspecified in (a), (b), (c), (d), (e), and (f), in a statisticallysignificant manner, and/or the presence in the test interferon of anyone or more, such as 2, or 3, or 4, or 5, of the activities specified in(g), (h), (i), (j), and (k), signifies that the test interferon andrSIFN-co or rSIFN-co substitute have substantially the same potency.

In another aspect, the present invention provides a method ofestablishing substantial equivalence between a test interferon andrSIFN-co or a rSIFN-co substitute comprising: (1) providing the testinterferon and rSIFN-co or rSIFN-co substitute; and (2) determining anyone or more of the following activities of the test interferon andrSIFN-co or rSIFN-co substitute under same specified conditions,respectively: (a) Inhibition of in vivo cancer cell growth in any one ormore tumor-bearing animal models; (b) Reduction in cancer cellviability; (c) Inhibition of cancer cell migration; (d) Inhibition ofbeta-catenin/TCF transcriptional activity in cancer cells; (e)Down-regulation of expression of LRP6 and/or FZD6 in cancer cells; (f)Inhibition of expression of any one or more of: Axin2, CD24, Survivinand ID2 in cancer cells; (g) Inhibition of pseudopod formation in cancercells; (h) Inhibition of beta-catenin expression in cancer cells; (i)Up-regulation of expression of any one or more of: DKK-3, KLF-4, andBATF2 in cancer cells, such as in A549 cells or SW620 cells; (j) Higheraffinity binding to IFNAR1 and/or lower affinity binding to IFNAR2 ascompared to IFNα-2b; and (k) Lower susceptibility to inhibition by B18Rthan IFNα-2b in up-regulation of expression of p-STAT in cancer cells;whereby the presence in the test interferon of any 1, or 2, or 3, or 4,or 5, or 6 of the activities specified in (a), (b), (c), (d), (e), and(f), in a statistically significant manner, and/or the presence in thetest interferon of any one or more, such as 2, or 3, or 4, or 5 of theactivities specified in (g), (h), (i), (j), and (k), signifies that thetest interferon and rSIFN-co or rSIFN-co substitute are substantialequivalence. Optionally, the presence of reduction in tumor cellviability in vitro, such as in A549 cells and/or SW620 cells, incombination with inhibition of transcriptional activity ofbeta-catenin/TCF, such as in any one or more of: A549 cells, H1299cells, H460 cells and HT-29 cells, in a statistically significantmanner, and optionally, the additional presence of JAK/STAT signaling,all upon treatment or administration of the test interferon, indicatesubstantial equivalence between the test interferon and rSIFN-co.Further optionally, the determination of cell viability can be conductedupon treatment of the appropriate cells with the test interferon forabout 1 to about 6 days at, for example, about 10 mcg/ml. Optionally,the inhibition of beta-catenin/TCF transcriptional activity isdetermined in any one or more of cancer cells: A549, H1299, H460, orHT-29, for example, by treatment of these cells with about 10 mcg/ml ofthe test interferon for about 24 hr. Optionally, the JAK/STAT signalingis determined by determining the presence of phosphorylation of STATproteins, such as STAT1, STAT2 and/or STAT3, such as upon treatment ofA549 cells or Hela cells, with about 10 mcg/ml of the test interferonfor various times, such as about 5, 15, 30, 60, 120, and/or 240 minutes.

In some embodiments, in step (2) of above methods, at least 2 of thefore-mentioned activities on the test interferon and rSIFN-co orrSIFN-co substitute under same specified conditions are determined, suchas (a) and (b); (a) and (c); (a) and (d); (a) and (e); (a) and (f); (a)and (g); (a) and (h); (a) and (i); (a) and (j); (a) and (k); (b) and(c); (b) and (d); (b) and (e); (b) and (f); (b) and (g); (b) and (h);(b) and (i); (b) and (j); (b) and (k); (c) and (d); (c) and (e); (c) and(f); (c) and (g); (c) and (h); (c) and (i); (c) and (j); (c) and (k);(d) and (e); (d) and (f); (d) and (g); (d) and (h); (d) and (i); (d) and(j); (d) and (k); (e) and (f); (e) and (g); (e) and (h); (e) and (i);(e) and (j); (e) and (k); (f) and (g); (f) and (h); (f) and (i); (f) and(j); (f) and (k); (g) and (h); (g) and (i); (g) and (j); (g) and (k);(h) and (i); (h) and (j); (h) and (k); (i) and (j); (i) and (k); (j) and(k).

In some embodiments, in step (2) of above methods, at least 3 of thefore-mentioned activities on the test interferon and rSIFN-co orrSIFN-co substitute under same specified conditions are determined, suchas (a), (b) and (c); (a), (b) and (d); (a), (b) and (e); (a), (b) and(f); (a), (b) and (g); (a), (b) and (h); (a), (b) and (i); (a), (b) and(j); (a), (b) and (k); (a), (c) and (d); (a), (c) and (e); (a), (c) and(f); (a), (c) and (g); (a), (c) and (h); (a), (c) and (i); (a), (c) and(j); (a), (c) and (k); (a), (d) and (e); (a), (d) and (f); (a), (d) and(g); (a), (d) and (h); (a), (d) and (i); (a), (d) and (j); (a), (d) and(k); (a), (e) and (f); (a), (e) and (g); (a), (e) and (h); (a), (e) and(i); (a), (e) and (j); (a), (e) and (k); (a), (f) and (g); (a), (f) and(h); (a), (f) and (i); (a), (f) and (j); (a), (f) and (k); (a), (g) and(h); (a), (g) and (i); (a), (g) and (j); (a), (g) and (k); (a), (h) and(i); (a), (h) and (j); (a), (h) and (k); (a), (i) and (j); (a), (i) and(k); (a), (j) and (k); (b), (c) and (d); (b), (c) and (e); (b), (c) and(f); (b), (c) and (g); (b), (c) and (h); (b), (c) and (i); (b), (c) and(j); (b), (c) and (k); (b), (d) and (e); (b), (d) and (f); (b), (d) and(g); (b), (d) and (h); (b), (d) and (i); (b), (d) and (j); (b), (d) and(k); (b), (e) and (f); (b), (e) and (g); (b), (e) and (h); (b), (e) and(i); (b), (e) and (j); (b), (e) and (k); (b), (f) and (g); (b), (f) and(h); (b), (f) and (i); (b), (f) and (j); (b), (f) and (k); (b), (g) and(h); (b), (g) and (i); (b), (g) and (j); (b), (g) and (k); (b), (h) and(i); (b), (h) and (j); (b), (h) and (k); (b), (i) and (j); (b), (i) and(k); (b), (j) and (k); (c), (d) and (e); (c), (d) and (f); (c), (d) and(g); (c), (d) and (h); (c), (d) and (i); (c), (d) and (j); (c), (d) and(k); (c), (e) and (f); (c), (e) and (g); (c), (e) and (h); (c), (e) and(i); (c), (e) and (j); (c), (e) and (k); (c), (f) and (g); (c), (f) and(h); (c), (f) and (i); (c), (f) and (j); (c), (f) and (k); (c), (g) and(h); (c), (g) and (i); (c), (g) and (j); (c), (g) and (k); (c), (h) and(i); (c), (h) and (j); (c), (h) and (k); (c), (i) and (j); (c), (i) and(k); (c), (j) and (k); (d), (e) and (f); (d), (e) and (g); (d), (e) and(h); (d), (e) and (i); (d), (e) and (j); (d), (e) and (k); (d), (f) and(g); (d), (f) and (h); (d), (f) and (i); (d), (f) and (j); (d), (f) and(k); (d), (g) and (h); (d), (g) and (i); (d), (g) and (j); (d), (g) and(k); (d), (h) and (i); (d), (h) and (j); (d), (h) and (k); (d), (i) and(j); (d), (i) and (k); (d), (j) and (k); (e), (f) and (g); (e), (f) and(h); (e), (f) and (i); (e), (f) and (j); (e), (f) and (k); (e), (g) and(h); (e), (g) and (i); (e), (g) and (j); (e), (g) and (k); (e), (h) and(i); (e), (h) and (j); (e), (h) and (k); (e), (i) and (j); (e), (i) and(k); (e), (j) and (k); (f), (g) and (h); (f), (g) and (i); (f), (g) and(j); (f), (g) and (k); (f), (h) and (i); (f), (h) and (j); (f), (h) and(k); (f), (i) and (j); (f), (i) and (k); (f), (j) and (k); (g), (h) and(i); (g), (h) and (j); (g), (h) and (k); (g), (i) and (j); (g), (i) and(k); (g), (j) and (k); (h), (i) and (j); (h), (i) and (k); (h), (j) and(k); (i), (j) and (k).

In some embodiments, in step (2) of above methods, at least 4 of thefore-mentioned activities on the test interferon and rSIFN-co orrSIFN-co substitute under same specified conditions are determined, suchas (a), (b), (c) and (d); (a), (b), (c), and (e); (a), (b), (c) and (f);(a), (b), (c) and (g); (a), (b), (c) and (h); (a), (b), (c) and (i);(a), (b), (c) and (j); (a), (b), (c) and (k); (a), (c), (d) and (e);(a), (c), (d) and (f); (a), (c), (d) and (g); (a), (c), (d) and (h);(a), (c), (d) and (i); (a), (c), (d) and (j); (a), (c), (d) and (k);(a), (d), (e) and (f); (a), (d), (e) and (g); (a), (d), (e) and (h);(a), (d), (e) and (i); (a), (d), (e) and (j); (a), (d), (e) and (k);(a), (e), (f) and (g); (a), (e), (f) and (h); (a), (e), (f) and (i);(a), (e), (f) and (j); (a), (e), (f) and (k); (a), (f), (g) and (h);(a), (f), (g) and (i); (a), (f), (g) and (j); (a), (f), (g) and (k);(a), (g), (h) and (i); (a), (g), (h) and (j); (a), (g), (h) and (k);(a), (h), (i) and (j); (a), (h), (i) and (k); (a), (i), (j) and (k);(b), (c), (d) and (e); (b), (c), (d) and (f); (b), (c), (d) and (g);(b), (c), (d) and (h); (b), (c), (d) and (i); (b), (c), (d) and (j);(b), (c), (d) and (k); (b), (d), (e) and (f); (b), (d), (e) and (g);(b), (d), (e) and (h); (b), (d), (e) and (i); (b), (d), (e) and (j);(b), (d), (e) and (k); (b), (e), (f) and (g); (b), (e), (f) and (h);(b), (e), (f) and (i); (b), (e), (f) and (j); (b), (e), (f) and (k);(b), (f), (g), and (h); (b), (f), (g), and (i); (b), (f), (g), and (j);(b), (f), (g), and (k); (b), (g), (h), and (i); (b), (g), (h), and (j);(b), (g), (h), and (k); (b), (h), (i), and (j); (b), (h), (i), and (k);(b), (i), (j), and (k); (c), (d), (e), and (f); (c), (d), (e), and (g);(c), (d), (e), and (h); (c), (d), (e), and (i); (c), (d), (e), and (j);(c), (d), (e), and (k); (c), (d), (f) and (g); (c), (d), (f) and (h);(c), (d), (f) and (i); (c), (d), (f) and (j); (c), (d), (f) and (k);(c), (d), (g), and (h); (c), (d), (g) and (i); (c), (d), (g), and (j);(c), (d), (g), and (k); (c), (d), (h), and (i); (c), (d), (h), and (j);(c), (d), (h), and (k); (c), (e), (f) and (g); (c), (e), (f) and (h);(c), (e), (f) and (i); (c), (e), (f) and (i); (c), (e), (f) and (j);(c), (f), (g) and (h); (c), (f), (g) and (i); (c), (f), (g) and (j);(c), (f), (g) and (k); (c), (g), (h) and (i); (c), (g), (h) and (j);(c), (g), (h) and (k); (c), (h), (i), and (j); (c), (h), (i), and (k);(c), (i), (j), and (k); (d), (e), (f) and (g); (d), (e), (f) and (h);(d), (e), (f) and (i); (d), (e), (f) and (j); (d), (e), (f) and (k);(d), (f), (g), and (h); (d), (f), (g), and (i); (d), (f), (g), and (j);(d), (f), (g), and (k); (d), (g), (h) and (i); (d), (g), (h) and (j);(d), (g), (h) and (k); (d), (h), (i), and (j); (d), (h), (i), and (k);(d), (i), (j), and (k); (e), (f), (g) and (h); (e), (f), (g) and (i);(e), (f), (g) and (j); (e), (f), (g) and (k); (e), (g), (h) and (i);(e), (g), (h) and (j); (e), (g), (h) and (k); (e), (h), (i), and (j);(e), (h), (i), and (k); (e), (i), (j), and (k); (f), (g), (h) and (i);(f), (g), (h) and (j); (f), (g), (h), (i), and (k); (f), (h), (i), (i),and (k); (h), (i), and (k); (f), (i), (j), and (k); (g), (h), (i), and(j); (g), (h), (i), and (k); (g), (i), (j), and (k); (h), (i), (j), and(k).

In some embodiments, in step (2) of above methods, at least 5 of thefore-mentioned activities on the test interferon and rSIFN-co orrSIFN-co substitute under same specified conditions are determined, suchas (a), (b), (c), (d), and (e); (a), (b), (c), (d), and (f); (a), (b),(c), (d), and (g); (a), (b), (c), (d), and (h); (a), (b), (c), (d), and(i); (a), (b), (c), (d), and (j); (a), (b), (c), (d), and (k); (a), (c),(d), (e) and (f); (a), (c), (d), (e) and (g); (a), (c), (d), (e) and(h); (a), (c), (d), (e) and (i); (a), (c), (d), (e) and (j); (a), (c),(d), (e) and (k); (a), (d), (e), (f) and (g); (a), (d), (e), (f) and(h); (a), (d), (e), (f) and (i); (a), (d), (e), (f) and (j); (a), (d),(e), (f) and (k); (a), (e), (f), (g) and (h); (a), (e), (f), (g) and(i); (a), (e), (f), (g) and (j); (a), (e), (f), (g) and (k); (a), (f),(g), (h) and (i); (a), (f), (g), (h) and (j); (a), (f), (g), (h) and(k); (b), (c), (d), (e) and (f); (b), (c), (d), (e) and (g); (b), (c),(d), (e) and (h); (b), (c), (d), (e) and (i); (b), (c), (d), (e) and(j); (b), (c), (d), (e) and (k); (b), (d), (e), (f) and (g); (b), (d),(e), (f) and (h); (b), (d), (e), (f) and (i); (b), (d), (e), (f) and(j); (b), (d), (e), (f) and (k); (b), (e), (f), (g) and (h); (b), (e),(f), (g) and (i); (b), (e), (f), (g) and (j); (b), (e), (f), (g) and(k); (b), (f), (g), (h) and (i); (b), (f), (g), (h) and (j); (b), (f),(g), (h) and (k); (c), (d), (e), (f) and (g); (c), (d), (e), (f) and(h); (c), (d), (e), (f) and (i); (c), (d), (e), (f) and (j); (c), (d),(e), (f) and (k); (c), (e), (f), (g) and (h); (c), (e), (f), (g) and(i); (c), (e), (f), (g) and (j); (c), (e), (f), (g) and (k); (c), (f),(g), (h) and (i); (c), (f), (g), (h) and (j); (c), (f), (g), (h) and(k); (d), (e), (f), (g), and (h); (d), (e), (f), (g), and (i); (d), (e),(f), (g), and (j); (d), (e), (f), (g), and (k); (d), (f), (g), (h) and(i); (d), (f), (g), (h) and (j); (d), (f), (g), (h) and (k); (f), (g),(h), (i) and (j); (f), (g), (h), (i) and (k); (g), (h), (i), (j) and(k).

In some embodiments, in step (2) of above methods, at least 6 of thefore-mentioned activities on the test interferon and rSIFN-co orrSIFN-co substitute under same specified conditions are determined, suchas (a), (b), (c), (d), (e), and (f); (a), (b), (c), (d), (e), and (g);(a), (b), (c), (d), (e), and (h); (a), (b), (c), (d), (e), and (i); (a),(b), (c), (d), (e), and (j); (a), (b), (c), (d), (e), and (k); (a), (c),(d), (e), (f), and (g); (a), (c), (d), (e), (f), and (h); (a), (c), (d),(e), (f), and (i); (a), (c), (d), (e), (f), and (j); (a), (c), (d), (e),(f), and (k); (a), (d), (e), (f), (g) and (h); (a), (d), (e), (f), (g)and (i); (a), (d), (e), (f), (g) and (j); (a), (d), (e), (f), (g) and(k); (a), (e), (f), (g), (h) and (i); (a), (e), (f), (g), (h) and (j);(a), (e), (f), (g), (h) and (k); (b), (c), (d), (e), (f), and (g); (b),(c), (d), (e), (f), and (h); (b), (c), (d), (e), (f), and (i); (b), (c),(d), (e), (f), and (j); (b), (c), (d), (e), (f), and (k); (b), (d), (e),(f), (g) and (h); (b), (d), (e), (f), (g) and (i); (b), (d), (e), (f),(g) and (j); (b), (d), (e), (f), (g) and (k); (b), (e), (f), (g), (h)and (i); (b), (e), (f), (g), (h) and (j); (b), (e), (f), (g), (h) and(k); (c), (d), (e), (f), (g), and (h); (c), (d), (e), (f), (g), and (j);(c), (d), (e), (f), (g), and (k); (c), (d), (e), (f), (g), and (i); (c),(d), (e), (f), (g), and (j); (c), (d), (e), (f), (g), and (k); (c), (e),(f), (g), (h) and (i); (c), (e), (f), (g), (h) and (j); (c), (e), (f),(g), (h) and (k); (d), (e), (f), (g), (h) and (i); (d), (e), (f), (g),(h) and (j); (d), (e), (f), (g), (h) and (k).

In some embodiments, in step (2) of above methods, at least 7 of thefore-mentioned activities on the test interferon and rSIFN-co orrSIFN-co substitute under same specified conditions are determined, suchas (a), (b), (c), (d), (e), (f), and (g); (a), (b), (c), (d), (e), (f),and (h); (a), (b), (c), (d), (e), (f), and (i); (a), (b), (c), (d), (e),(f), and (j); (a), (b), (c), (d), (e), (f), and (k); (a), (c), (d), (e),(f), (g) and (h); (a), (c), (d), (e), (f), (g) and (i); (a), (c), (d),(e), (f), (g) and (j); (a), (c), (d), (e), (f), (g) and (k); (a), (d),(e), (f), (g), (h) and (i); (a), (d), (e), (f), (g), (h) and (j); (a),(d), (e), (f), (g), (h) and (k); (b), (c), (d), (e), (f), (g) and (h);(b), (c), (d), (e), (f), (g) and (i); (b), (c), (d), (e), (f), (g) and(j); (b), (c), (d), (e), (f), (g) and (k); (b), (d), (e), (f), (g), (h)and (i); (b), (d), (e), (f), (g), (h) and (j); (b), (d), (e), (f), (g),(h) and (k); (c), (d), (e), (f), (g), (h) and (i); (c), (d), (e), (f),(g), (h) and (j); (c), (d), (e), (f), (g), (h) and (k).

In some embodiments, in step (2) of above methods, at least 8 of thefore-mentioned activities on the test interferon and rSIFN-co orrSIFN-co substitute under same specified conditions are determined, suchas (a), (b), (c), (d), (e), (f), (g) and (h); (a), (b), (c), (d), (e),(f), (g) and (i); (a), (b), (c), (d), (e), (f), (g) and (j); (a), (b),(c), (d), (e), (f), (g) and (k); (b), (c), (d), (e), (f), (g), (h) and(i); (b), (c), (d), (e), (f), (g), (h) and (j); (b), (c), (d), (e), (f),(g), (h) and (k); (a), (c), (d), (e), (f), (g), (h) and (i); (a), (c),(d), (e), (f), (g), (h) and (j); (a), (c), (d), (e), (f), (g), (h) and(k); (a), (b), (d), (e), (f), (g), (h) and (i); (a), (b), (d), (e), (f),(g), (h) and (j); (a), (b), (d), (e), (f), (g), (h) and (k); (a), (b),(c), (e), (f), (g), (h) and (i); (a), (b), (c), (e), (f), (g), (h) and(j); (a), (b), (c), (e), (f), (g), (h) and (k); (a), (b), (c), (d), (f),(g), (h) and (i); (a), (b), (c), (d), (f), (g), (h) and (j); (a), (b),(c), (d), (f), (g), (h) and (k); (a), (b), (c), (d), (e), (g), (h) and(i); (a), (b), (c), (d), (e), (g), (h) and (j); (a), (b), (c), (d), (e),(g), (h) and (k); (a), (b), (c), (d), (e), (f), (h) and (i); (a), (b),(c), (d), (e), (f), (h) and (j); (a), (b), (c), (d), (e), (f), (h) and(k); (a), (b), (c), (d), (e), (f), (g) and (i); (a), (b), (c), (d), (e),(f), (g) and (j); (a), (b), (c), (d), (e), (f), (g) and (k).

In some embodiments, in step (2) of above methods, at least 9, 10, orall 11 of the fore-mentioned activities on the test interferon andrSIFN-co or rSIFN-co substitute under same specified conditions aredetermined, such as (a), (b), (c), (d), (e), (f), (g), (h), (i), (j) and(k).

In some embodiments, in determining activity (a), when as compared tocontrol, the presence in the test interferon of activity specified in(a) in a statistically significant manner (such as, p<0.05, optionally,p<0.01, further optionally, p<0.005, more optionally, p<0.001, stilloptionally, p<0.0005, still more optionally, p<0.0001), signifies thatthe test interferon and rSIFN-co or rSIFN-co substitute havesubstantially the same potency and/or are substantial equivalence.

In some embodiments, the tumor-bearing animal models employed indetermining activity (a) comprise mice, optionally, nude mice, moreoptionally, BALB/cA nu/nu mice. In some embodiments, the mice, such asthe BALB/cA nu/nu mice, comprise about 3 weeks old to about 7 weeks oldmice, optionally, comprise about 4 weeks old to about 6 weeks old mice.In some embodiments, the body weight of the mice, such as the BALB/cAnu/nu mice, is in a range of about 15±2 g to about 30±2 g; optionally,in a range of about 19±2 g to about 23±2 g.

In some embodiments, the cancer cells employed in determining activity(a), inhibition of in vivo cancer cell growth, comprise any one or moreof: liver cancer cells, cervical cancer cells, colon cancer cells, andlung cancer cells. In some embodiments, the cancer cells employed indetermining activity (a) comprise any one or more of: SMMC-7721 cells,Hela cells, HT-29 cells, SPC-A4 cells, and A549 cells; optionally,comprise any one or more of: HT-29 cells, SPC-A4 cells, and A549 cells;further optionally, comprise A549 cells.

In some embodiments, normal saline or PBS, optionally, normal saline isused as control in determining inhibition in activity (a). In someembodiments, the test interferon and/or rSIFN-co or rSIFN-co substituteadministered to a tumor-bearing animal model in determining activity(a), is administered in a range of about 0.02 mg to about 0.30 mg;optionally, about 0.05 mg to about 0.15 mg; further optionally, about0.075 mg to about 0.10 mg. In some embodiments, the test interferonand/or rSIFN-co or rSIFN-co substitute, administered to a tumor-bearinganimal model in determining activity (a), is administered every otherday. In some embodiments, the test interferon and/or rSIFN-co orrSIFN-co substitute, administered to a tumor-bearing animal model indetermining activity (a), is administered for about 2 weeks to about 6weeks; optionally, about 3 weeks to about 4 weeks. In some embodiments,the control administered to a tumor-bearing animal model in determiningactivity (a), is administered in a range of about 0.05 ml to about 0.30ml; optionally, about 0.10 ml to about 0.20 ml. In some embodiments, thecontrol, administered to a tumor-bearing animal model in determiningactivity (a), is administered every other day. In some embodiments, thecontrol, administered to a tumor-bearing animal model in determiningactivity (a), is administered for about 2 weeks to about 6 weeks;optionally, about 3 weeks to about 4 weeks. In some embodiments, thetest interferon and/or control is administered intratumorally.

In some embodiments, in determining activity (a), when SMMC-7721 cellsare employed in determining activity (a), as compared to control (suchas normal saline), the presence in the test interferon of activityspecified in (a) in a statistically significant manner (such as p<0.05for about 0.05 mg and about 0.10 mg, optionally, p<0.01 for about 0.15mg), signifies that the test interferon and rSIFN-co or rSIFN-cosubstitute have substantially the same potency and/or are substantialequivalence. In some embodiments, the test interferon and/or rSIFN-co orrSIFN-co substitute is administered every other day in a range of about0.02 mg to about 0.30 mg; optionally, about 0.05 mg to about 0.15 mg;further optionally, about 0.075 mg to about 0.10 mg, for about 3 weeks.

In some embodiments, in determining activity (a), when Hela cells areemployed in determining activity (a), as compared to control (such asnormal saline), the presence in the test interferon of activityspecified in (a) in a statistically significant manner (such as p<0.05for about 0.15 mg, optionally, p<0.01 for about 0.05 mg and about 0.10mg), signifies that the test interferon and rSIFN-co or rSIFN-cosubstitute have substantially the same potency and/or are substantialequivalence. In some embodiments, the test interferon and/or rSIFN-co orrSIFN-co substitute is administered every other day in a range of about0.02 mg to about 0.30 mg; optionally, about 0.05 mg to about 0.15 mg;further optionally, about 0.075 mg to about 0.10 mg, for about 4 weeks.

In some embodiments, in determining activity (a), when HT-29 cells areemployed in determining activity (a), as compared to control (such asnormal saline), the presence in the test interferon of activityspecified in (a) in a statistically significant manner (such as p<0.01for about 0.10 mg and 0.15 mg, optionally, p<0.001 for about 0.05 mg),signifies that the test interferon and rSIFN-co or rSIFN-co substitutehave substantially the same potency and/or are substantial equivalence.In some embodiments, the test interferon and/or rSIFN-co or rSIFN-cosubstitute is administered every other day in a range of about 0.02 mgto about 0.30 mg; optionally, about 0.05 mg to about 0.15 mg; furtheroptionally, about 0.075 mg to about 0.10 mg, for about 4 weeks.

In some embodiments, in determining activity (a), when SPC-A4 cells areemployed in determining activity (a), as compared to control (such asnormal saline), the presence in the test interferon of activityspecified in (a) in a statistically significant manner (such as p<0.01for about 0.05 mg, about 0.10 mg and about 0.15 mg), signifies that thetest interferon and rSIFN-co or rSIFN-co substitute have substantiallythe same potency and/or are substantial equivalence. In someembodiments, the test interferon and/or rSIFN-co or rSIFN-co substituteis administered every other day in a range of about 0.02 mg to about0.30 mg; optionally, about 0.05 mg to about 0.15 mg; further optionally,about 0.075 mg to about 0.10 mg, for about 3 weeks.

In some embodiments, in determining activity (a), when A549 cells areemployed in determining activity (a), as compared to control (such asPBS), the presence in the test interferon of activity specified in (a)in a statistically significant manner (such as p<0.0001), signifies thatthe test interferon and rSIFN-co or rSIFN-co substitute havesubstantially the same potency and/or are substantial equivalence. Insome embodiments, the test interferon and/or rSIFN-co or rSIFN-cosubstitute is administered every other day in a range of about 0.02 mgto about 0.30 mg; optionally, about 0.05 mg to about 0.15 mg, moreoptionally, about 0.10 mg, for at least about 3 weeks.

In some embodiments, in determining activity (b), reduction in cancercell viability, when the test interferon causes about 50% reduction inviability of the cancer cells at a concentration in a range of betweenabout 6.25 mcg/ml and about 25 mcg/ml; optionally, between about 10mcg/ml and about 18 mcg/ml; more optionally, between about 10 mcg/ml andabout 15 mcg/ml, signifies that the test interferon and rSIFN-co orrSIFN-co substitute have substantially the same potency and/or aresubstantial equivalence. In some embodiments, in determining activity(b), when the test interferon causes reduction in cancer cell viabilityto a substantially undetectable level at a concentration in a range ofat least about 25 mcg/ml; optionally, at least about 50 mcg/ml; furtheroptionally, at least about 75 mcg/ml; more optionally, at least about100 mcg/ml, signifies that the test interferon and rSIFN-co or rSIFN-cosubstitute have substantially the same potency and/or are substantialequivalence.

In some embodiments, in determining activity (b), the concentrations ofthe test interferon and/or rSIFN-co or rSIFN-co substitute compriseconcentrations in a range of between about 0.2 mcg/ml and about 100mcg/ml. In some embodiments, the concentrations of the test interferonand/or rSIFN-co or rSIFN-co substitute are at least two or more of thefollowing: 0.2 mcg/ml, 0.39 mcg/ml, 0.78 mcg/ml, 1.56 mcg/ml, 3.13mcg/ml, 6.25 mcg/ml, 12.5 mcg/ml, 25 mcg/ml, 50 mcg/ml, and 100 mcg/ml.In some embodiments, in determining activity (b), the cancer cells aretreated by the test interferon and/or rSIFN-co or rSIFN-co substitutefor at least about 1 day; optionally, at least about 2 days.

In some embodiments, the cancer cells employed in determining activity(b) comprise any one or more of: lung cancer cells, colon cancer cells,cervical cancer cells, liver cancer cells, breast cancer cells, andpancreatic cancer cells; optionally, comprise any one or more of: lungcancer cells, colon cancer cells, liver cancer cells, breast cancercells, and pancreatic cancer cells. In some embodiments, the cancercells employed in determining activity (b) comprise any one or more of:A549 cells, Hela cells, CL-1 cells, Huh-7 cells, SW480 cells, MDA-MB-231cells, Calu-1 cells, SMMC-7721 cells, and PANC-1 cells; optionally,comprise any one or more of: A549 cells, CL-1 cells, Huh-7 cells, SW480cells, MDA-MB-231 cells, Calu-1 cells, SMMC-7721 cells, and PANC-1cells.

In some embodiments, in determining activity (b), when the testinterferon causes about 50% reduction in viability of any one or moreof: SW480 cells, MDA-MB-231 cells, and PANC-1 cells at a concentrationin a range of between about 6.25 mcg/ml and about 12.5 mcg/ml, signifiesthat the test interferon and rSIFN-co or rSIFN-co substitute havesubstantially the same potency and/or are substantial equivalence.

In some embodiments, in determining activity (b), when the testinterferon causes about 50% reduction in viability of any one or moreof: A549 cells, Hela cells, CL-1 cells, Huh-7 cells, Calu-1 cells, andSMMC-7721 cells at a concentration in a range of between about 12.5mcg/ml and about 25 mcg/ml, signifies that the test interferon andrSIFN-co or rSIFN-co substitute have substantially the same potencyand/or are substantial equivalence.

In some embodiments, in determining activity (b), when A549 cells and/orSW620 cells are employed in determining activity (b), as compared tocontrol (such as IFNα-2b), the presence in the test interferon ofactivity specified in (b) in a statistically significant manner (such asp<0.01), signifies that the test interferon and rSIFN-co or rSIFN-cosubstitute have substantially the same potency and/or are substantialequivalence. In some embodiments, the cancer cells employed indetermining activity (b) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute in a range of about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml. In some embodiments, the cancercells employed in determining activity (b) are treated for about 1 dayto about 10 days; optionally, about 1 day to about 6 days.

In some embodiments, in determining activity (b), the cancer cellviability is determined by Am-Blue method or MTT method.

In some embodiments, in determining activity (c), when as compared tocontrol, the presence in the test interferon of activity specified in(c) in a statistically significant manner (such as, p<0.01), signifiesthat the test interferon and rSIFN-co or rSIFN-co substitute havesubstantially the same potency and/or are substantial equivalence. Insome embodiments, the control is untreated control (Mock).

In some embodiments, the cancer cells employed in determining activity(c), inhibition of cancer cell migration, comprise any one or more of:lung cancer cells, and colon cancer cells. In some embodiments, thecancer cells employed in determining activity (c) comprise any one ormore of: A549 cells, and SW620 cells. In some embodiments, theinhibition of cancer cell migration in activity (c) is determined usingTranswell method. In some embodiments, the cancer cells employed indetermining activity (c) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute in a range of about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml. In some embodiments, the cancercells employed in determining activity (c) are treated by the testinterferon and/or rSIFN-co or rSIFN-co substitute for at least about 20hours; optionally, at least about 24 hours.

In some embodiments, in determining activity (d), when as compared tocontrol, the presence in the test interferon of activity specified in(d) in a statistically significant manner (such as, p<0.05, optionally,p<0.01), signifies that the test interferon and rSIFN-co or rSIFN-cosubstitute have substantially the same potency and/or are substantialequivalence. In some embodiments, the control is untreated control(Mock).

In some embodiments, the cancer cells employed in determining activity(d), inhibition of beta-catenin/TCF transcriptional activity in cancercells, comprise any one or more of: lung cancer cells, and colon cancercells. In some embodiments, the cancer cells employed in determiningactivity (d) comprise any one or more of: A549 cells, H1299 cells, H460cells, HT-29 cells, and SW620 cells; optionally, comprise any one ormore of: A549 cells, H1299 cells, H460 cells, and SW620 cells. In someembodiments, the cancer cells in employed in determining activity (d)are treated by the test interferon and/or rSIFN-co or rSIFN-cosubstitute for at least about 20 hours; optionally, at least about 24hours. In some embodiments, the cancer cells employed in determiningactivity (d) are treated by the test interferon and/or rSIFN-co orrSIFN-co substitute in a range of about 5 mcg/ml to about 20 mcg/ml;optionally, about 10 mcg/ml. In some embodiments, the transcriptionalactivity of beta-catenin/TCF is determined by use of a reporter system.In some embodiments, the reporter system comprises TOPFlash or pSV40-RLplasmid.

In some embodiments, in determining activity (e), when as compared tocontrol, the presence in the test interferon of activity specified in(e) in a statistically significant manner (such as, p<0.005, optionally,p<0.001, further optionally, p<0.0005), signifies that the testinterferon and rSIFN-co or rSIFN-co substitute have substantially thesame potency and/or are substantial equivalence. In some embodiments,the control is untreated control (Mock).

In some embodiments, the cancer cells employed in determining activity(e), down-regulation of expression of LRP6 and/or FZD6 in cancer cells,comprise any one or more of: lung cancer cells, and colon cancer cells.In some embodiments, the cancer cells employed in determining activity(e) comprise any one or more of: A549 cells, H460 cells, SW620 cells,and HT-29 cells; optionally, comprise any one or more of: A549 cells,SW620 cells, and HT-29 cells; more optionally, comprise HT-29 cells. Insome embodiments, the cancer cells employed in determining activity (e)are treated by the test interferon and/or rSIFN-co or rSIFN-cosubstitute for at least about 20 hours; optionally, at least about 24hours. In some embodiments, the cancer cells employed in determiningactivity (e) are treated by the test interferon and/or rSIFN-co orrSIFN-co substitute in a range of about 5 mcg/ml to about 20 mcg/ml;optionally, about 10 mcg/ml. In some embodiments, in determiningactivity (e) the expression of LRP6 and/or FZD6 is determined bydetermining mRNA level of LRP6 and/or FZD6. In some embodiments, whenmRNA level is determined, GAPDH is used as control.

In some embodiments, in determining activity (f), when as compared tocontrol, the presence in the test interferon of activity specified in(f) in a statistically significant manner (such as, p<0.0005,optionally, p<0.0001), signifies that the test interferon and rSIFN-coor rSIFN-co substitute have substantially the same potency and/or aresubstantial equivalence. In some embodiments, the control is untreatedcontrol (Mock).

In some embodiments, the cancer cells employed in determining activity(f), inhibition of expression of any one or more of: Axin2, CD24,Survivin and ID2, comprise lung cancer cells; optionally, comprise A549cells. In some embodiments, the cancer cells employed in determiningactivity (f) are treated by the test interferon and/or rSIFN-co orrSIFN-co substitute for at least about 20 hours; optionally, at leastabout 24 hours. In some embodiments, the cancer cells employed indetermining activity (f) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute in a range of about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml. In some embodiments, in determiningactivity (f) the expression of Axin2, CD24, Survivin and/or ID2 isdetermined by determining its corresponding mRNA level. In someembodiments, when mRNA level is determined, GAPDH is used as control.

In some embodiments, in determining activity (f), when the testinterferon decreases at least about 30%; optionally, at least about 40%;more optionally, at least about 50%; still more optionally, at leastabout 60% in expression of any one or more of: Axin2, CD24, Survivin andID2 in the cancer cells as compared to control, the test interferonand/or rSIFN-co or rSIFN-co substitute are considered to havesubstantially the same potency and/or substantial equivalence.

In some embodiments, in determining activity (g), when the pseudopodformation in cancer cells is substantially inhibited by the testinterferon, signifies that the test interferon and rSIFN-co or rSIFN-cosubstitute have substantially the same potency and/or are substantialequivalence. For purposes herein, “substantially inhibited” means atleast about 60% inhibition; optionally, at least about 70% inhibition;still optionally, at least about 80% inhibition; further optionally, atleast about 90% inhibition; still further optionally, at least about 95%inhibition.

In some embodiments, the cancer cells employed in determining activity(g), inhibition of pseudopod formation, comprise lung cancer cells;optionally, A549 cells. In some embodiments, the cancer cells employedin determining activity (g) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute for at least about 4 days; optionally,at least about 8 days. In some embodiments, the cancer cells employed indetermining activity (g) are treated by the test interferon and/orrSIFN-co or rSIFN-co substitute in a range of about 5 mcg/ml to about 20mcg/ml; optionally, about 10 mcg/ml. In some embodiments, the cancercells employed in determining activity (g) are cultured in Matrigel.

In some embodiments, in determining activity (h), when the level ofbeta-catenin in the cancer cells is significantly decreased by the testinterferon, signifies that the test interferon and rSIFN-co or rSIFN-cosubstitute have substantially the same potency and/or are substantialequivalence. For purposes herein, the level of beta-catenin in cancercells is significantly decreased after treatment when, e.g. on a WesternBlot, the band representing the protein becomes faint or absent ascompared to that before treatment.

In some embodiments, the cancer cells employed in determining activity(h), inhibition of beta-catenin expression in cancer cells, comprise anyone or more of: lung cancer cells and colon cancer cells. In someembodiments, the cancer cells employed in determining activity (h)comprise any one or more of: A549 cells and SW480 cells. In someembodiments, in determining activity (h) the inhibition of beta-cateninexpression is determined by Western Blot. In some embodiments, thecancer cells employed in determining activity (h) are treated by thetest interferon and/or rSIFN-co or rSIFN-co substitute for at leastabout 48 hours; optionally, at least about 72 hours. In someembodiments, the cancer cells employed in determining activity (h) aretreated by the test interferon and/or rSIFN-co or rSIFN-co substitute ina range of about 5 mcg/ml to about 20 mcg/ml; optionally, about 10mcg/ml.

In some embodiments, in determining activity (i), when the testinterferon can more effective up-regulate the expression of any one ormore of: DKK-3, KLF-4, and BATF2 in cancer cells as compared to IFNα-2b,signifies that the test interferon and rSIFN-co or rSIFN-co substitutehave substantially the same potency and/or are substantial equivalence.

In some embodiments, the cancer cells employed in determining activity(i), up-regulation of expression of any one or more of: DKK-3, KLF-4,and BATF2 in cancer cells, comprise any one or more of: lung cancercells, and colon cancer cells. In some embodiments, the cancer cellsemployed in determining activity (i) comprise any one or more of: A549cells, H460 cells, SW620 cells, and HT-29 cells; optionally, compriseany one or more of: A549 cells, and SW620 cells. In some embodiments,the cancer cells employed in determining activity (i) are treated by thetest interferon and/or rSIFN-co or rSIFN-co substitute for at leastabout 20 hours; optionally, at least about 24 hours. In someembodiments, the cancer cells employed in determining activity (i) aretreated by the test interferon and/or rSIFN-co or rSIFN-co substitute ina range of about 5 mcg/ml to about 20 mcg/ml; optionally, about 10mcg/ml. In some embodiments, in determining activity (i) the expressionof DKK-3, KLF-4 and/or BATF2 is determined by determining itscorresponding mRNA level. In some embodiments, when mRNA level isdetermined, GAPDH is used as control.

In some embodiments, statistical significance means a p value of lessthan or equal to 0.05, or less than or equal to 0.01, or less than orequal to 0.005, or less than or equal to 0.001, or less than or equal to0.0005, or less than or equal to 0.0001, when compared to a control.

In some embodiments, the control is not treated with the test interferonor rSIFN-co or rSIFN-co substitute, or is treated with normal saline orPBS, or is treated with IFNα-2b, or the control is untreated control(Mock).

In one aspect, the present invention provides a method of determining orcomparing the potency of a compound, such as a test interferon,comprising: (a) providing a plurality of concentrations of the testinterferon; (b) determining a first dose response of the testinterferon, using the plurality of concentrations of the testinterferon, on the viability of a first set of cancer cells underspecified conditions; (c) providing a plurality of concentrations ofrSIFN-co or a substitute of rSIFN-co (hereafter, “rSIFN-co substitute”);(d) determining a second dose response of the rSIFN-co or rSIFN-cosubstitute, using the plurality of concentrations of the rSIFN-co or therSIFN-co substitute, on viability of a second set of cancer cells underthe same specified conditions; and (e) comparing the first dose responsewith the second dose response. In such a manner, the potency of thecompound, such as the test interferon, is determined relative torSIFN-co or rSIFN-co substitute.

In some embodiments of the invention, the rSIFN-co (SEQ ID NO:1) is madeas described in U.S. Pat. No. 7,364,724 (Recombinant Super-CompoundInterferon) by expression of the novel polynucleotide (SEQ ID NO:2) in aE. coli host, optionally under the control of promoter P_(BAD) in a E.coli host. In some embodiments of the invention, the rSIFN-co isobtainable by a process comprising introducing into E. coli thepolynucleotide sequence shown in SEQ ID NO:2. In some embodiments of theinvention, the rSIFN-co has the amino acid sequence of SEQ ID NO: 1, andis encoded by the nucleotide sequence of SEQ ID NO: 2, wherein theinterferon has increased inhibitory activities on the expression ofhepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) ofHepatitis B Virus as compared to an interferon not encoded by thenucleotide sequence of SEQ ID NO: 2, such as interferon alfacon-1(INFERGEN®).

In some embodiments, the rSIFN-co used in the methods herein comprises aspecified specific activity, and the specific activity can be, forexample, in the range between about 4×10⁸ IU/mg to about 1×10⁹ IU/mg. Insome embodiments, the specific activity is in the range between about4.4×10⁸ IU/mg to about 9×10⁸ IU/mg. In some embodiments, the specificactivity is in the range between about 5×10⁸ IU/mg to about 8×10⁸ IU/mg.In some embodiments, the specific activity is in the range between about6×10⁸ IU/mg to about 7.5×10⁸ IU/mg. Optionally, the specific activity isin the range between about 4×10⁸ IU/mg to 5×10⁸ IU/mg.

In some embodiments, in the methods of determining or comparing thepotency of a compound, the concentrations of the test interferon orrSIFN-co are in a range between about 0.2 mcg/ml and about 100 mcg/ml.In some embodiments, the concentrations of the test interferon orrSIFN-co are at least two or more of the following: 0.2 mcg/ml, 0.39mcg/ml, 0.78 mcg/ml, 1.56 mcg/ml, 3.13 mcg/ml, 6.25 mcg/ml, 12.5 mcg/ml,25 mcg/ml, 50 mcg/ml, and 100 mcg/ml.

In some embodiments, the cells used in the methods herein fordetermining the effect of rSIFN-co are cancer cells, whether human oranimal cells. The cells are treated with the test interferon or rSIFN-cofor at least about 24 hr, optionally, at least about 48 hr, and stilloptionally, at least about 72 hr, and unless otherwise stated, understandard cultural conditions, in complete medium, at 37° C., in a 5% CO₂atmosphere. The culture medium can be any standard complete mediumsuitable for culture of tumor cells, such as that available fromShanghai Cell Collection (Shanghai, China) and supplemented with 10%fetal bovine serum (Biochrom, Germany), 4 mM glutamine, 50 U/mlpenicillin and 50 mg/ml streptomycin. The IFN alpha-2b may be obtainedfrom Shanghai Hua-xin High Biotechnology, Inc. (Shanghai, China) andrSIFN-co may be obtained from Sichuan Huiyang Life-Engineering Co., Ltd.(Chengdu, China).

In some embodiments, the invention provides rSIFN-co that has theability to reduce viability of the cancer cells by 50% at aconcentration in the range of between about 6.25 mcg/ml and about 25mcg/ml, depending on the cancer cell type. In some embodiments, therSIFN-co is capable of reducing viability of the cells by 50% at aconcentration in the range of between about 6.25 mcg/ml and 12.5 mcg/ml.In another embodiment, the rSIFN-co is capable of reducing viability ofthe cells by 50% at a concentration in the range of between about 12.5mcg/ml and 25 mcg/ml. In some embodiments, the IC50 of the rSIFN-co isin the range of about 10 mcg/ml to about 18 mcg/ml.

In some embodiments, the test interferon is also an interferon, but isobtained from a different manufacturing lot than the rSIFN-co being usedin the comparison.

Thus, for example, in determining the potency of a compound such as atest interferon, the test interferon is diluted to variousconcentrations, and a certain number of prepared cells appropriate forthe container being used, such as 5×103 cells in 100 microliter ofcomplete medium, are incubated for a certain period of time with suchvarious concentrations of the test interferon, such as 48 hr. Afterincubation, the viability of the cells are determined and compared withthe viability of cells similarly treated but with rSIFN-co instead ofthe test interferon. The dose response curves for each of the testinterferon-treated and rSIFN-co-treated cells can be generated from theresults and compared. In such a manner, the potency of the testinterferon, in terms of 50% effective dose or IC50 can be determinedrelative to that of the rSIFN-co.

In another aspect, the present invention provides a method ofdetermining or comparing potency of a compound, such as a testinterferon, relative to rSIFN-co or rSIFN-co substitute, on viability ofcancer cells, comprising: (a) providing a plurality of cancer cells; (b)testing a first set of the cancer cells with an amount of the testinterferon under specified conditions to generate a first set ofviability data; (c) treating a second set of the cancer cells with aneffective amount of rSIFN-co or rSIFN-co substitute under the samespecified conditions to generate a second set of viability data; and (d)comparing the first set of viability data with the second set ofviability data, whereby the potency of the test interferon isdetermined.

In some embodiments, the cancer cells are treated for a range from about1 day to about 6 days. In some embodiments, the rSIFN-co is used at aconcentration in the range of about 6.25 mcg/ml to about 50 mcg/ml;optionally, about 7 mcg/ml to about 25 mcg/ml; further optionally, about8 mcg/ml to about 12.5 mcg/ml; still optionally, about 10 mcg/ml. Insome embodiments, the rSIFN-co or comprises a specified specificactivity.

In some embodiments, the cancer cells used herein are chosen from amonghuman tumor cells and animal tumor cells. In some embodiments, the tumorcells are lung tumor cells, or cervical tumor cells, or liver tumorcells, or colon tumor cells, or breast tumor cells, or pancreatic tumorcells, or prostate tumor cells, or viral-induced tumor cells or virallytransformed cells. In some embodiments, the cancer cells are chosen fromat least one of: A549 cells, Calu-1 cells, CL-1 cells, H460, H1299, Helacells, HT29, Huh-7 cells, MDA-MB-231 cells, PANC-1, RAW264.7, SMMC-7721cells, SW480 cells, and SW620 cells.

Thus, for example, a certain number of cancer cells in an appropriatevolume suitable for the test container, such as 2×10³ cells in 100microliter of complete medium, can be placed in 96 well plates andeither treated with about 10 mcg/ml of the test interferon or rSIFN-coor left untreated as control, for 1, 2, 3, 4, 5, or 6 days, and theviability of the treated cells determined on each day relative to theviability of the untreated control. At the conclusion of the experiment,the viability of the treated cells relative to that of the untreatedcontrol can be plotted against the number of days of interferontreatment. In this way, the ability of the test compound to reduceviability of cancer cells can be compared and its potency determinedrelative to that of rSIFN-co.

In some embodiments, the present invention provides a method ofinhibiting cell migration, such as that occurring in tumor metastases,comprising exposing the cells to an effective amount of rSIFN-co, for aspecified period of time, whereby cell migration is inhibited.

In some embodiments, exposure of the cells, such as tumor cells, torSIFN-co as mentioned herein can be effected in vitro or in vivo, byincubating the cells in the presence of an effective amount of rSIFN-coat 37° C. for a period of time, such as for 24 hr, or by administrationof an effective amount of the rSIFN-co to animals or subjects such thata certain concentration of the rSIFN-co is maintained for a period oftime sufficient to obtain the desired effect, such as inhibition oftumor cell migration as in metastases, or inhibition of pseudopodformation, inhibition of beta-catenin/TCF transcriptional activity,inhibition of expression of beta-catenin protein, down-regulation ofWnt-related receptors and/or co-receptors, down-regulation of Wntsignaling downstream target genes, up-regulation of tumor suppressorgenes, and others as described herein.

The cell migration assay may be performed using any suitablecommercially available kits. For example, an 8 micrometer insertcontaining a microporous membrane placed in a 24-well plate fromBecton-Dickinson Biosciences (N.J., USA) can be used herein. For theassay, warm bicarbonate based culture medium at 37° C. without FBS canbe added to the interior of the inserts and the bottom of the wells, andallowed to rehydrate for about 2 hr in a humidified tissue cultureincubator at 37° C., in 5% CO₂ atmosphere. After rehydration, the mediumcan be carefully removed and about 500 microliter of the prepared cells(such as cells pretreated with rSIFN-co for 24 hr at 37° C.), suspendedin FBS-free medium can be seeded onto the upper sides of the insertfilters at a density of about 0.5×10⁴ cells/insert. Then 500 microliterof complete medium with 10% FBS can be added to the lower compartment ofthe 24-well plates. The cells/inserts/plate can then be incubated at 37°C. for about 24 hr, and the non-migrated cells on the upper side of thechamber membranes can be removed, such as with a cotton swab. The lowersurfaces of the culture inserts containing the migrated cells can befixed, such as with 4% paraformaldehyde and stained with 2% crystalviolet. The number of migrated cells on the opposite side of the chambermembranes can be counted and the mean number of migrating cells perfield determined. In this way, the ability of the test interferon toinhibit tumor cell migration can be demonstrated.

In some embodiments, the effective amount of the rSIFN-co comprisesabout 5 mcg/ml to about 100 mcg/ml; optionally, about 8 mcg/ml to about50 mcg/ml; still optionally, about 10 mcg/ml to about 25 mcg/ml; furtheroptionally, about 12 mcg/ml to about 18 mcg/ml.

In another aspect, the invention provides a method of inhibitingpseudopod formation in cancer cells, comprising exposing the cancercells to an effective amount of rSIFN-co, for a specified period oftime, whereby pseudopod formation is inhibited.

In a further aspect, the invention provides a method of inhibitingbeta-catenin/TCF-mediated transcriptional activity in cells, comprisingexposing the cells to an effective amount of rSIFN-co for a specifiedperiod of time.

In some embodiments, the beta-catenin/TCF-mediated transcriptionalactivity can be determined using a luciferase reporter system. In someembodiments, the reporter system is TOPFlash reporter. In someembodiments, the plasmid pSV40-RL is used. Thus, for example, the cellsto be assessed can be plated onto 96-well plates, such as at about 1×10⁴cells per well, and incubated for about 12 hr at 37° C., after which,they are transiently transfected with about 100 ng of TOPFlash(Millipore Corporation, Billerica, Mass., USA). For normalization oftransfection efficiency, the cells can be further co-transfected with 1ng of internal control reporter Renilla reniformis luciferase drivenunder the SV40 promoter (pRL-SV40) (Promega, Madison, Wis.). After 6 hrof transfection, the cells for in vitro analysis can then be treatedwith rSIFN-co for about 24 hr. After rSIFN-co treatment for in vitroanalysis or after transfection for the in vivo analysis, luciferaseassay can be performed using the Dual Luciferase Assay System kitaccording to the manufacturer's protocols (Cat #: E1960, Promega).Relative luciferase activity can be determined as a ratio offirefly/renilla luciferase activity.

In another aspect, the invention additionally provides a method ofdecreasing beta-catenin protein level in cells comprising exposing cellsto an effective amount of rSIFN-co for a specified period of time. Insome embodiments, the protein level of beta-catenin is detected byWestern Blot using its specific antibody. In some embodiments, GAPDH isused as a control.

For Western Blot analysis to determine the level of beta-catenin in thecells, cell from in vitro culture or from in vivo tumor samples,standard procedures can be employed. For example, total cellularproteins can be extracted using extraction reagents (Cat #: P0013)following manufacturer's protocol (Beyotime, China). Proteinconcentrations can be determined with Bio-Rad Lowry protein assaysystem. Total proteins can be separated by SDS-PAGE on 10%-12% gel andthen transferred to a 0.45 micrometer nitrocellulose membrane (MilliporeCorporation, Billerica, Mass., USA). The membrane can be blocked withblocking buffer (5% bovine serum albumin, 10 mmol/L Tris-HCl, ph 8.0,150 mol/L NaCl, and 0.05% Tween 20) overnight at 4° C., then incubatedwith primary antibodies (1:1000 dilution) followed by secondaryHRP-conjugated antibodies. The antibodies can be from any vendor, forexample, the following antibodies can be used: mouse monoclonalanti-beta-catenin (1:1000, Santa Cruz Technology, Santa Cruz, Calif.),mouse monoclonal anti-GAPDH (1:2000, Kangwei Biotechnology, China), andanti-mouse HRP-conjugated secondary antibody (1:2000, Santa CruzTechnology). Blots can be visualized using Luminescence/FluorescenceImaging LAS4000 System (GE Healthcare Life Sciences, USA) with supersignal west pico chemiluminescent substrate kit (Thermo Scientific,USA).

In another aspect, the invention provides a method for down-regulatingexpression of a Wnt-related receptor or co-receptor in cells, comprisingexposing the cells to an effective amount of rSIFN-co for a specifiedtime, whereby the Wnt-related receptor or co-receptor is down-regulated.In some embodiments, the Wnt-related receptor or co-receptor comprises aLRP protein, such as LRP6. In some embodiments, the Wnt-signalingreceptor or co-receptor comprises a FZD protein, such as FZD6. As statedabove, the method of exposing cells to rSIFN-co can be an in vitromethod or an in vivo method.

In some embodiments, determining the expression of the Wnt-relatedreceptor or co-receptor comprises determining the mRNA level of suchreceptor or co-receptor. Such mRNA level can be determined by anystandard methods. In some embodiments, cDNA corresponding to such mRNAis made to determine such mRNA levels. For example, total mRNA can beisolated using TRIZOL Reagent (Invitrogen, Carlsbad, Calif.) accordingto manufacturer's instructions. Complementary DNA (cDNA) can besynthesized using a RT-PCT Kit (Cat #: FSQ-101, TOYOBO, Japan) accordingto manufacturer's instructions and then subjected to quantitative PCR(qPCR) with a SYBR Green PCR kit (Cat #: QPK-201, TOYOBO, Japan).Suitable primers can be used. For example, the primers for LRP6 can besense primers: 5′-TGAAGAACCAGCACCACAGG-3′ (SEQ ID NO: 4); antisenseprimers: 5′-CATAACCAAGAGGCACAGAAGC-3′ (SEQ ID NO:5), and the primers forFZD6 can be sense primers: 5′-GCGGAGTGAAGGAAGGATTAGTC-3′ (SEQ ID NO: 6);and antisense primers: 5′-TGAACAAGCAGAGATGTGGAACC-3′ (SEQ ID NO: 7). Theamplification protocol can be incubations at 95° C. for 1 minute, 40cycles (95° C. for 15 seconds, 60° C. for 15 seconds, and 72° C. for 30seconds). Incorporation of the SYBR Green dye into the PCR products canbe monitored in real time with a Bio-Rad Detection System and thenanalyzed using Bio-Rad CFX manager 2.1 software. The samples can bepooled for each condition and run in duplicated. The interferon-treatedsamples can be compared with the Mock untreated samples using the2^(−ΔΔ)Ct method and plotted as fold change. GAPDH can be used as anormalization control. This 2^(−ΔΔ) Ct method is conventionally used toanalyze relative changes in gene expression from real-time quantitativePCR experiments.

In a further aspect, the invention provides a method of down-regulatingthe expression of certain genes in cells, including at least one targetgene of the Wnt-signaling pathway, such as for the treatment of adisease or condition in which the target gene is mutated or isover-active. Such down-regulated genes include, for example, one or moreof Axin2, CD24, Survivin, and/or ID2. The method comprises exposing thecells to an effective amount of rSIFN-co for a specified period of time,whereby expression of the target gene is inhibited. The extent ofdown-regulated can be determined by standard techniques such as by qPCRas previously mentioned. For example, for such qPCR, for Axin2, thesense primers: 5′-CGTGGATACCTTAGACTT-3′ (SEQ ID NO: 8) and the antisenseprimers: 5′-GCTGTTGTTCTCAATGTA-3′ (SEQ ID NO: 9) can be used; for CD24,the sense primers: 5′-TGAAGAACATGTGAGAGGTTTGAC-3′ (SEQ ID NO: 10) andthe antisense primers: 5′-GAAAACTGAATCTCCATTCCACAA-3′ (SEQ ID NO: 11)can be used; for Survivin, the sense primers: 5′-ACCGCATCTCTACATTCAAG-3′(SEQ ID NO: 12) and the antisense primers:-5′CAAGTCTGGCTCGTTCTC-3′(SEQID NO: 13) can be used; and for ID2, the sense primers:5′-CACAACAACAACAACAAC-3′ (SEQ ID NO: 14) and antisense primers:5′-CACAGTCCAAGTAAGAGA-3′ (SEQ ID NO: 15) can be used.

In some embodiments of the invention, the specified period of time forexposure of cells to rSIFN-co is at least about 12 hr; optionally, atleast about 24 hr; further optionally, for at least about 36 hr; stilloptionally, at least for about 48 hr; yet still optionally, at leastabout 72 hr. In some embodiments, the cells being treated by rSIFN-coare cancer cells.

In a further aspect, the invention provides a method of up-regulatingexpression of certain genes in cells, including at least one tumorsuppressor gene, comprising exposing the cells to an effective amount ofrSIFN-co for a specified period of time, whereby up-regulation ofexpression at least one tumor suppressor gene is effected. In someembodiments, the up-regulated gene comprises at least one of DKK3, KLF4,and BATF2. The extent of up-regulation of such genes can be determinedby standard techniques. In some embodiments, the expression of theup-regulated gene is determined by measuring mRNA level. In someembodiments, cDNA is synthesized from such mRNA and is optionallyamplified for such measurement purposes. As an example, foramplification purposes, the following primers can be used: for BATF2,sense primers: 5′-CAGAGCAGGGAGCACAAACC-3′ (SEQ ID NO: 16) and antisenseprimers: 5′-TGAGCAGAGGAGAGCAGAGG-3′ (SEQ ID NO: 17); for DKK3, senseprimers: 5′-GGAGCCTGACTGAAGAGATGG-3′(SEQ ID NO: 18) and antisenseprimers: 5′-ACGCCTAAAGCACACACCTG-3′ (SEQ ID NO: 19); for KLF4, senseprimers: 5′-CCTTCAACCTGGCGGACATCAAC-3′ (SEQ ID NO: 20) and antisenseprimers: 5′-GGCTGCTGCGGCGGAATG-3′ (SEQ ID NO: 21).

In another aspect, the invention provides a method of establishingsubstantial equivalence between a test compound and rSIFN-co or rSIFN-cosubstitute in at least one, optionally at least 2, 3, 4, 5, 6, 7, 8, 9,10 or 11 of the following, comprising comparing the activities theretoand showing substantially the same responses: (a) Inhibition of in vivocancer cell growth in any one or more tumor-bearing animal models; (b)Reduction in cancer cell viability; (c) Inhibition of cancer cellmigration; (d) Inhibition of beta-catenin/TCF transcriptional activityin cancer cells; (e) Down-regulation of expression of LRP6 and/or FZD6in cancer cells; (f) Inhibition of expression of any one or more of:Axin2, CD24, Survivin and ID2 in cancer cells; (g) Inhibition ofpseudopod formation in cancer cells; (h) Inhibition of beta-cateninexpression in cancer cells; (i) Up-regulation of expression of any oneor more of: DKK-3, KLF-4, and BATF2 in cancer cells, such as in A549cells or SW620 cells; (j) Higher affinity binding to IFNAR1 and/or loweraffinity binding to IFNAR2 as compared to IFNα-2b; and (k) Lowersusceptibility to inhibition by B18R than IFNα-2b in up-regulation ofexpression of p-STAT in cancer cells. In some embodiments, the inventionprovides establishing substantial equivalence in at least 2 of thefore-mentioned activities, such as (a) and (b); (a) and (c); (a) and(d); (a) and (e); (a) and (f); (a) and (g); (a) and (h); (a) and (i);(a) and (j); (a) and (k); (b) and (c); (b) and (d); (b) and (e); (b) and(f); (b) and (g); (b) and (h); (b) and (i); (b) and (j); (b) and (k);(c) and (d); (c) and (e); (c) and (f); (c) and (g); (c) and (h); (c) and(i); (c) and (j); (c) and (k); (d) and (e); (d) and (f); (d) and (g);(d) and (h); (d) and (i); (d) and (j); (d) and (k); (e) and (f); (e) and(g); (e) and (h); (e) and (i); (e) and (j); (e) and (k); (f) and (g);(f) and (h); (f) and (i); (f) and (j); (f) and (k); (g) and (h); (g) and(i); (g) and (j); (g) and (k); (h) and (i); (h) and (j); (h) and (k);(i) and (j); (i) and (k); (j) and (k); optionally, the inventionprovides establishing substantial equivalence in at least 3 of thefore-mentioned activities, such as (a), (b) and (c); (a), (b) and (d);(a), (b) and (e); (a), (b) and (f); (a), (b) and (g); (a), (b) and (h);(a), (b) and (i); (a), (b) and (j); (a), (b) and (k); (a), (c) and (d);(a), (c) and (e); (a), (c) and (f); (a), (c) and (g); (a), (c) and (h);(a), (c) and (i); (a), (c) and (j); (a), (c) and (k); (a), (d) and (e);(a), (d) and (f); (a), (d) and (g); (a), (d) and (h); (a), (d) and (i);(a), (d) and (j); (a), (d) and (k); (a), (e) and (f); (a), (e) and (g);(a), (e) and (h); (a), (e) and (i); (a), (e) and (j); (a), (e) and (k);(a), (f) and (g); (a), (f) and (h); (a), (f) and (i); (a), (f) and (j);(a), (f) and (k); (a), (g) and (h); (a), (g) and (i); (a), (g) and (j);(a), (g) and (k); (a), (h) and (i); (a), (h) and (j); (a), (h) and (k);(a), (i) and (j); (a), (i) and (k); (a), (j) and (k); (b), (c) and (d);(b), (c) and (e); (b), (c) and (f); (b), (c) and (g); (b), (c) and (h);(b), (c) and (i); (b), (c) and (j); (b), (c) and (k); (b), (d) and (e);(b), (d) and (f); (b), (d) and (g); (b), (d) and (h); (b), (d) and (i);(b), (d) and (j); (b), (d) and (k); (b), (e) and (f); (b), (e) and (g);(b), (e) and (h); (b), (e) and (i); (b), (e) and (j); (b), (e) and (k);(b), (f) and (g); (b), (f) and (h); (b), (f) and (i); (b), (f) and (j);(b), (f) and (k); (b), (g) and (h); (b), (g) and (i); (b), (g) and (j);(b), (g) and (k); (b), (h) and (i); (b), (h) and (j); (b), (h) and (k);(b), (i) and (j); (b), (i) and (k); (b), (j) and (k); (c), (d) and (e);(c), (d) and (f); (c), (d) and (g); (c), (d) and (h); (c), (d) and (i);(c), (d) and (j); (c), (d) and (k); (c), (e) and (f); (c), (e) and (g);(c), (e) and (h); (c), (e) and (i); (c), (e) and (j); (c), (e) and (k);(c), (f) and (g); (c), (f) and (h); (c), (f) and (i); (c), (f) and (j);(c), (f) and (k); (c), (g) and (h); (c), (g) and (i); (c), (g) and (j);(c), (g) and (k); (c), (h) and (i); (c), (h) and (j); (c), (h) and (k);(c), (i) and (j); (c), (i) and (k); (c), (j) and (k); (d), (e) and (f);(d), (e) and (g); (d), (e) and (h); (d), (e) and (i); (d), (e) and (j);(d), (e) and (k); (d), (f) and (g); (d), (f) and (h); (d), (f) and (i);(d), (f) and (j); (d), (f) and (k); (d), (g) and (h); (d), (g) and (i);(d), (g) and (j); (d), (g) and (k); (d), (h) and (i); (d), (h) and (j);(d), (h) and (k); (d), (i) and (j); (d), (i) and (k); (d), (j) and (k);(e), (f) and (g); (e), (f) and (h); (e), (f) and (i); (e), (f) and (j);(e), (f) and (k); (e), (g) and (h); (e), (g) and (i); (e), (g) and (j);(e), (g) and (k); (e), (h) and (i); (e), (h) and (j); (e), (h) and (k);(e), (i) and (j); (e), (i) and (k); (e), (j) and (k); (f), (g) and (h);(f), (g) and (i); (f), (g) and (j); (f), (g) and (k); (f), (h) and (i);(f), (h) and (j); (f), (h) and (k); (f), (i) and (j); (f), (i) and (k);(f), (j) and (k); (g), (h) and (i); (g), (h) and (j); (g), (h) and (k);(g), (i) and (j); (g), (i) and (k); (g), (j) and (k); (h), (i) and (j);(h), (i) and (k); (h), (j) and (k); (i), (j) and (k); optionally, in atleast 4 of the fore-mentioned activities, such as (a), (b), (c) and (d);(a), (b), (c), and (e); (a), (b), (c) and (f); (a), (b), (c) and (g);(a), (b), (c) and (h); (a), (b), (c) and (i); (a), (b), (c) and (j);(a), (b), (c) and (k); (a), (c), (d) and (e); (a), (c), (d) and (f);(a), (c), (d) and (g); (a), (c), (d) and (h); (a), (c), (d) and (i);(a), (c), (d) and (j); (a), (c), (d) and (k); (a), (d), (e) and (f);(a), (d), (e) and (g); (a), (d), (e) and (h); (a), (d), (e) and (i);(a), (d), (e) and (j); (a), (d), (e) and (k); (a), (e), (f) and (g);(a), (e), (f) and (h); (a), (e), (f) and (i); (a), (e), (f) and (j);(a), (e), (f) and (k); (a), (f), (g) and (h); (a), (f), (g) and (i);(a), (f), (g) and (j); (a), (f), (g) and (k); (a), (g), (h) and (i);(a), (g), (h) and (j); (a), (g), (h) and (k); (a), (h), (i) and (j);(a), (h), (i) and (k); (a), (i), (j) and (k); (b), (c), (d) and (e);(b), (c), (d) and (f); (b), (c), (d) and (g); (b), (c), (d) and (h);(b), (c), (d) and (i); (b), (c), (d) and (j); (b), (c), (d) and (k);(b), (d), (e) and (f); (b), (d), (e) and (g); (b), (d), (e) and (h);(b), (d), (e) and (i); (b), (d), (e) and (j); (b), (d), (e) and (k);(b), (e), (f) and (g); (b), (e), (f) and (h); (b), (e), (f) and (i);(b), (e), (f) and (j); (b), (e), (f) and (k); (b), (f), (g), and (h);(b), (f), (g), and (i); (b), (f), (g), and (j); (b), (f), (g), and (k);(b), (g), (h), and (i); (b), (g), (h), and (j); (b), (g), (h), and (k);(b), (h), (i), and (j); (b), (h), (i), and (k); (b), (i), (j), and (k);(c), (d), (e), and (f); (c), (d), (e), and (g); (c), (d), (e), and (h);(c), (d), (e), and (i); (c), (d), (e), and (j); (c), (d), (e), and (k);(c), (d), (f) and (g); (c), (d), (f) and (h); (c), (d), (f) and (i);(c), (d), (f) and (j); (c), (d), (f) and (k); (c), (d), (g), and (h);(c), (d), (g) and (i); (c), (d), (g), and (j); (c), (d), (g), and (k);(c), (d), (h), and (i); (c), (d), (h), and (j); (c), (d), (h), and (k);(c), (e), (f) and (g); (c), (e), (f) and (h); (c), (e), (f) and (i);(c), (e), (f) and (i); (c), (e), (f) and (j); (c), (f), (g) and (h);(c), (f), (g) and (i); (c), (f), (g) and (j); (c), (f), (g) and (k);(c), (g), (h) and (i); (c), (g), (h) and (j); (c), (g), (h) and (k);(c), (h), (i), and (j); (c), (h), (i), and (k); (c), (i), (j), and (k);(d), (e), (f) and (g); (d), (e), (f) and (h); (d), (e), (f) and (i);(d), (e), (f) and (j); (d), (e), (f) and (k); (d), (f), (g), and (h);(d), (f), (g), and (i); (d), (f), (g), and (j); (d), (f), (g), and (k);(d), (g), (h) and (i); (d), (g), (h) and (j); (d), (g), (h) and (k);(d), (h), (i), and (j); (d), (h), (i), and (k); (d), (i), (j), and (k);(e), (f), (g) and (h); (e), (f), (g) and (i); (e), (f), (g) and (j);(e), (f), (g) and (k); (e), (g), (h) and (i); (e), (g), (h) and (j);(e), (g), (h) and (k); (e), (h), (i), and (j); (e), (h), (i), and (k);(e), (i), (j), and (k); (f), (g), (h) and (i); (f), (g), (h) and (j);(f), (g), (h) and (k); (f), (h), (i), and (j); (f), (h), (i), and (k);(f), (i), (j), and (k); (g), (h), (i), and (j); (g), (h), (i), and (k);(g), (i), (j), and (k); (h), (i), (j), and (k); still optionally, in atleast 5 of the fore-mentioned activities, such as (a), (b), (c), (d),and (e); (a), (b), (c), (d), and (f); (a), (b), (c), (d), and (g); (a),(b), (c), (d), and (h); (a), (b), (c), (d), and (i); (a), (b), (c), (d),and (j); (a), (b), (c), (d), and (k); (a), (c), (d), (e) and (f); (a),(c), (d), (e) and (g); (a), (c), (d), (e) and (h); (a), (c), (d), (e)and (i); (a), (c), (d), (e) and (j); (a), (c), (d), (e) and (k); (a),(d), (e), (f) and (g); (a), (d), (e), (f) and (h); (a), (d), (e), (f)and (i); (a), (d), (e), (f) and (j); (a), (d), (e), (f) and (k); (a),(e), (f), (g) and (h); (a), (e), (f), (g) and (i); (a), (e), (f), (g)and (j); (a), (e), (f), (g) and (k); (a), (f), (g), (h) and (i); (a),(f), (g), (h) and (j); (a), (f), (g), (h) and (k); (b), (c), (d), (e)and (f); (b), (c), (d), (e) and (g); (b), (c), (d), (e) and (h); (b),(c), (d), (e) and (i); (b), (c), (d), (e) and (j); (b), (c), (d), (e)and (k); (b), (d), (e), (f) and (g); (b), (d), (e), (f) and (h); (b),(d), (e), (f) and (i); (b), (d), (e), (f) and (j); (b), (d), (e), (f)and (k); (b), (e), (f), (g) and (h); (b), (e), (f), (g) and (i); (b),(e), (f), (g) and (j); (b), (e), (f), (g) and (k); (b), (f), (g), (h)and (i); (b), (f), (g), (h) and (j); (b), (f), (g), (h) and (k); (c),(d), (e), (f) and (g); (c), (d), (e), (f) and (h); (c), (d), (e), (f)and (i); (c), (d), (e), (f) and (j); (c), (d), (e), (f) and (k); (c),(e), (f), (g) and (h); (c), (e), (f), (g) and (i); (c), (e), (f), (g)and (j); (c), (e), (f), (g) and (k); (c), (f), (g), (h) and (i); (c),(f), (g), (h) and (j); (c), (f), (g), (h) and (k); (d), (e), (f), (g),and (h); (d), (e), (f), (g), and (i); (d), (e), (f), (g), and (j); (d),(e), (f), (g), and (k); (d), (f), (g), (h) and (i); (d), (f), (g), (h)and (j); (d), (f), (g), (h) and (k); (f), (g), (h), (i) and (j); (f),(g), (h), (i) and (k); (g), (h), (i), (j) and (k); further optionally,in at least 6 of the fore-mentioned activities, such as (a), (b), (c),(d), (e), and (f); (a), (b), (c), (d), (e), and (g); (a), (b), (c), (d),(e), and (h); (a), (b), (c), (d), (e), and (i); (a), (b), (c), (d), (e),and (j); (a), (b), (c), (d), (e), and (k); (a), (c), (d), (e), (f), and(g); (a), (c), (d), (e), (f), and (h); (a), (c), (d), (e), (f), and (i);(a), (c), (d), (e), (f), and (j); (a), (c), (d), (e), (f), and (k); (a),(d), (e), (f), (g) and (h); (a), (d), (e), (f), (g) and (i); (a), (d),(e), (f), (g) and (j); (a), (d), (e), (f), (g) and (k); (a), (e), (f),(g), (h) and (i); (a), (e), (f), (g), (h) and (j); (a), (e), (f), (g),(h) and (k); (b), (c), (d), (e), (f), and (g); (b), (c), (d), (e), (f),and (h); (b), (c), (d), (e), (f), and (i); (b), (c), (d), (e), (f), and(j); (b), (c), (d), (e), (f), and (k); (b), (d), (e), (f), (g) and (h);(b), (d), (e), (f), (g) and (i); (b), (d), (e), (f), (g) and (j); (b),(d), (e), (f), (g) and (k); (b), (e), (f), (g), (h) and (i); (b), (e),(f), (g), (h) and (j); (b), (e), (f), (g), (h) and (k); (c), (d), (e),(f), (g), and (h); (c), (d), (e), (f), (g), and (j); (c), (d), (e), (f),(g), and (k); (c), (d), (e), (f), (g), and (i); (c), (d), (e), (f), (g),and (j); (c), (d), (e), (f), (g), and (k); (c), (e), (f), (g), (h) and(i); (c), (e), (f), (g), (h) and (j); (c), (e), (f), (g), (h) and (k);(d), (e), (f), (g), (h) and (i); (d), (e), (f), (g), (h) and (j); (d),(e), (f), (g), (h) and (k); still further optionally, in at least 7 ofthe fore-mentioned activities, such as (a), (b), (c), (d), (e), (f), and(g); (a), (b), (c), (d), (e), (f), and (h); (a), (b), (c), (d), (e),(f), and (i); (a), (b), (c), (d), (e), (f), and (j); (a), (b), (c), (d),(e), (f), and (k); (a), (c), (d), (e), (f), (g) and (h); (a), (c), (d),(e), (f), (g) and (i); (a), (c), (d), (e), (f), (g) and (j); (a), (c),(d), (e), (f), (g) and (k); (a), (d), (e), (f), (g), (h) and (i); (a),(d), (e), (f), (g), (h) and (j); (a), (d), (e), (f), (g), (h) and (k);(b), (c), (d), (e), (f), (g) and (h); (b), (c), (d), (e), (f), (g) and(i); (b), (c), (d), (e), (f), (g) and (j); (b), (c), (d), (e), (f), (g)and (k); (b), (d), (e), (f), (g), (h) and (i); (b), (d), (e), (f), (g),(h) and (j); (b), (d), (e), (f), (g), (h) and (k); (c), (d), (e), (f),(g), (h) and (i); (c), (d), (e), (f), (g), (h) and (j); (c), (d), (e),(f), (g), (h) and (k); yet further optionally, in at least 8 of thefore-mentioned activities, such as (a), (b), (c), (d), (e), (f), (g) and(h); (a), (b), (c), (d), (e), (f), (g) and (i); (a), (b), (c), (d), (e),(f), (g) and (j); (a), (b), (c), (d), (e), (f), (g) and (k); (b), (c),(d), (e), (f), (g), (h) and (i); (b), (c), (d), (e), (f), (g), (h) and(j); (b), (c), (d), (e), (f), (g), (h) and (k); (a), (c), (d), (e), (f),(g), (h) and (i); (a), (c), (d), (e), (f), (g), (h) and (j); (a), (c),(d), (e), (f), (g), (h) and (k); (a), (b), (d), (e), (f), (g), (h) and(i); (a), (b), (d), (e), (f), (g), (h) and (j); (a), (b), (d), (e), (f),(g), (h) and (k); (a), (b), (c), (e), (f), (g), (h) and (i); (a), (b),(c), (e), (f), (g), (h) and (j); (a), (b), (c), (e), (f), (g), (h) and(k); (a), (b), (c), (d), (f), (g), (h) and (i); (a), (b), (c), (d), (f),(g), (h) and (j); (a), (b), (c), (d), (f), (g), (h) and (k); (a), (b),(c), (d), (e), (g), (h) and (i); (a), (b), (c), (d), (e), (g), (h) and(j); (a), (b), (c), (d), (e), (g), (h) and (k); (a), (b), (c), (d), (e),(f), (h) and (i); (a), (b), (c), (d), (e), (f), (h) and (j); (a), (b),(c), (d), (e), (f), (h) and (k); (a), (b), (c), (d), (e), (f), (g) and(i); (a), (b), (c), (d), (e), (f), (g) and (j); (a), (b), (c), (d), (e),(f), (g) and (k); or optionally, at least 9, 10, or all 11 of thefore-mentioned activities, such as (a), (b), (c), (d), (e), (f), (g),(h), (i), (j) and (k).

In another aspect, the present invention provides assay kits comprising(a) rSIFN-co or rSIFN-co substitute and (b) at least one of:instructions for performing one or more of the methods described hereinand reagents for performing such methods. The reagent may includePhosphate Buffered Saline (PBS) or a buffer. In some embodiments, therSIFN-co or rSIFN-co substitute in the assay kit comprises a specifiedspecific activity.

In some embodiments, the test interferon also signals through theJAK/STAT signaling pathway in cancer cells and/or shares the commonIFNAR1/2 receptor with rSIFN-co, and is, hence, a substantialequivalence of rSIFN-co or has substantially the same potency asrSIFN-co. In some embodiments signaling through the JAK/STAT pathway isdetected by means of detecting the presence of phosphorylated proteinsfrom the STAT family, such as STAT1, STAT2 and/or STAT3. In someembodiments, Western Blots are used for such detection. In someembodiments, cancer cells A549 and/or Hela cells can be used for suchdetection. In some embodiments, the cancer cells are treated with about10 mcg/ml of the test interferon or the rSIFN-co. In some embodimentsthe cancer cells are treated with the test interferon or rSIFN-co forabout 5, 15, 30, 60, 120, and/or 240 minutes. In some embodiments, aftertreatment with the interferon, cellular proteins are collected for theWestern Blot analysis. In some embodiments, GAPDH is used as a control.

In some embodiments, the tests or activities to be performed toestablish equivalence or potency to rSIFN-co or rSIFN-co substitute canbe conducted in any conventional manner and are not limited to mannerdisclosed herein.

EXAMPLES

The invention herein is further illustrated by the following examples,but the examples are not intended to limit the scope of the invention.The invention may be practiced in the presence or absence of any elementor elements, limitation or limitations, not specifically mentioned butis recognized to be useful by one of ordinary skill in the art. Further,the descriptions of the invention herein are not intended to belimitations but, unless otherwise specified, should be read to includeequivalents or modifications of the features, elements or limitationsdescribed, or portions thereof as understood by a person of ordinaryskill in the art. It is understood that various other embodiments may bepracticed, given the general description provided herein. Other objects,features, and advantages of the invention will become apparent to thoseskilled in the art from the foregoing, and from the detailed descriptionand examples and appended claims, in conjunction with the accompanyingdrawings.

All data are displayed as means±standard deviation (SD). T-tests (andnonparametric tests) were applied to analyze the relationship betweenthe different variables. Statistical significance was assumed whenp<0.05.

Example 1. Activity of rSIFN-Co on Human Hepatoma

This study was conducted to demonstrate the activity and efficacy ofrSIFN-co on human hepatoma, using human hepatoma SMMC-7721 as a model,in an in vivo system. The activity of the test article, rSIFN-co, wascompared with that of Mitomycin C (“MMC”). rSIFN-co, a colorless liquid,at a concentration of 1 mg/ml, was provided by Huiyang Life Science andTechnology Corp. (Chengdu, P.R. China). The test article was usedwithout dilution. It was stored at 4° C. until thawed for injection.Mitomycin C (“MMC”), lot #505 AGB, at a concentration of 2 mg/vial, wasprovided by Kyowa Hakko Kogyo Co., Ltd. (Japan). MMC was diluted withnormal saline at the time of injection.

The animal experiments were operated in accordance with the NationalInstitutes of Health Guide for the Care and Use of Laboratory Animals.

The animals used were 4-6 weeks old male BALB/cA nu/nu mice, weighingabout 23±2 g, obtained from the Shanghai Institute of Materia Medica(Shanghai, P.R. China). The study protocol was reviewed by the Committeeon the Use and Care of Animals of Shanghai Institute of Materia Medicafor compliance with regulations, and Committee approval was obtainedprior to study initiation. Wherever possible, procedures used in thisstudy were designed to avoid or minimize discomfort, distress, and painto the animals. Animals that experience severe or chronic pain ordistress that could not be relieved were painlessly euthanized, inaccordance to regulations. Animals were housed 6 to a cage. They wereear-marked with ear hole punch identification. The room temperature wasmaintained at 25° C.±+1° C. Lighting was set at 12 hr on and 12 hr off.Food was provided ad libitum. City tap water, filtered with a 5micrometer (μm) filter, was provided to the animals ad libitum via waterbottles. Neither the Study Director nor Huiyang Life Science andTechnology Corp. was aware of any contaminant in the food or water thatwould interfere with or influence the intent and purpose of this study.

The test article (rSIFN-co) and the vehicle control were eachadministered intratumorally (i.t.). The test article was administered ina volume of 0.05 ml-0.15 ml per mouse per treatment, depending on thegroup to which the animal was assigned. MMC was administeredintravenously (i.v.) at 10 microliter (l)/g. Normal saline was injectedin a volume of 0.15 ml per mouse, which was used as vehicle control.

Animals were assigned to treatment groups randomly. Initially, allanimals were placed in one large animal cage. For assignment to thestudy, they were later separately housed, with 6 animals per cage pertreatment group. The dose and dosing regimen for each group were as setforth in Table 1. Groups 1 and 2 are Control groups in which the animalswere each administered the vehicle every other day after the firsttreatment. The animals in Group 3 were given MMC at a dose of 5 mg/kg ondays 1 and 6 after initiation of treatment. The animals in Groups 4, 5and 6 were each given rSIFN-co every other day after the first treatmentat 0.15 mg/mouse (Group 4) or 0.10 mg/mouse (Group 5) or 0.05 mg/mouse(Group 6), respectively. Tumor growth was monitored by measuring thelength and width of each tumor twice a week during the course of thestudy. Each animal was also weighed twice a week during the course ofthe study.

The tumors, human hepatoma SMMC-7721 xenografts, were established ineach animal by inoculating 5×10⁶ cells subcutaneously (s.c.) into eachmouse. Before commencement of this study, the xenografts were passagedtwice in nude mice. Under sterile conditions, well-grown tumors were cutinto 1.5 mm³ fragments and one such fragment was injected by trocarneedle into the right flank of each study animal. When tumors reached avolume in the range of 100 mm³-200 mm³, the mice were randomized toeither control or treated groups and each group received either vehicle(Groups 1 and 2), rSIFN-co (Groups 4, 5 and 6) or MMC (Group 3) at thedoses and under the schedule set forth in Table 1, for a period of 3weeks. Individual tumor size (length and width) was measured twice perweek with microcalipers. Tumor volume (V) was calculated using theformula: V=(length×width²)/2. Individual relative tumor volume (RTV) wascalculated using the formula: RTV=Vt/V₀, where Vt is the tumor volume onthe day of measurement and V₀ is the tumor volume on the day of firsttreatment. Therapeutic effect of the test article or control article wasexpressed in terms of T/C (%), using the formula: T/C (%)=(mean RTV ofthe treated group/mean RTV of the control group)×100%; and in terms of %Inhibition, using the formula: % Inhibition=100%−T/C %.

TABLE 1 Dose Levels and Group Identification for Example 1. Group nTreatment Dose Dosing Schedule 1 6 Vehicle NA Every other day 2 6Vehicle NA Every other day 3 6 MMC 5 mg/kg d 1 and d 16 4 6 rSIFN-co0.15 mg/mouse Every other day 5 6 rSIFN-co 0.10 mg/mouse Every other day6 6 rSIFN-co 0.05 mg/mouse Every other day

Results are shown in Table 2 and FIG. 1. Table 2 shows, for eachtreatment group, the beginning tumor size on day 0, the ending tumorsize on day 21, as well as the calculated mean RTV, T/C % and %Inhibition.

TABLE 2 Activity of rSIFN-co on human hepatoma SMMC-7721 TV(mm³, TV(mm³,mean ± SD) mean ± SD) RTV T/C % Treatment (D 0) (D 21) (mean ± SD) (%)Inhibition P value normal saline 129 ± 26 1172 ± 302  9.36 ± 3.9  (12mice) MMC 125 ± 35 621 ± 247 5.05 ± 2.1* 52.82 47.18 p < 0.05 0.15 mg123 ± 20 505 ± 226  4.13 ± 1.9** 43.20 56.80 p < 0.01 rSIFN-co 0.10 mg124 ± 15 573 ± 287 4.57 ± 2.3* 47.80 52.20 p < 0.05 rSIFN-co 0.05 mg 124± 26 592 ± 139 4.97 ± 1.7* 51.99 48.01 p < 0.05 rSIFN-co

Table 2 shows that rSIFN-co was active and effective in inhibitinggrowth of human hepatoma cells at all the 3 doses tested. The mean RTVon day 21 (D21) was 9.36±3.9 for the Vehicle Control group, 5.05±2.1 forthe MMC treated group, 4.13±1.9 for the 0.15 mg rSIFN-co-treated group,4.57±2.3 for the 0.10 mg rSIFN-co-treated group, and 4.97±1.7 for the0.05 mg rSIFN-co-treated group. The % Inhibition on day 21 (D21) was:47.18% for the MMC treated group, 56.80% for the 0.15 mgrSIFN-co-treated group, 52.20% for the 0.10 mg rSIFN-co-treated group,and 48.01% for the 0.05 mg rSIFN-co-treated group. The differences inRTV between each of the treated groups and the Vehicle Control groupwere determined to be statistically significant.

FIG. 1 shows the progression of growth of human hepatoma, SMMC-7721, innude mice, as represented by RTV, for each treatment group over the21-day study period, reflecting the tumor measurements made on days 3,7, 10, 14, 17 and 21 after the start of treatment. Results showretardation of tumor growth in each of the MMC-treated group andrSIFN-co-treated groups by day 7, which was maintained until day 21.Results also show a trend towards greater inhibition at higher doses ofrSIFN-co.

All animals treated with the test article tolerated the tested dosageswell with no signs of toxicity or weight loss. The mean body weights (ingram) of the animals for the Vehicle group, the MMC-treated group, the0.15 mg rSIFN-co-treated group, the 0.10 mg rSIFN-co-treated group, andthe 0.05 mg rSIFN-co-treated group were, respectively on day 0 (and day21): 22.7 (24.8); 23.9 (25.4); 23.7 (25.3); 24.3 (26.2); and 22.6(24.4).

Example 2. Activity of rSIFN-Co on Human Cervical Cancer

This study demonstrates the activity and efficacy of rSIFN-co ontreatment of human cervical tumor, using Hela cells as a model. Resultsshow that rSIFN-co was active and effective in inhibiting growth ofhuman cervical cancer cells. The study was conducted as in Example 1except as specifically indicated otherwise. Human cervical cancerxenografts were first established and prepared in a similar manner as inExample 1, by inoculating 5×10⁶ Hela cells subcutaneously in nude miceand passaging the well-grown xenografts twice in nude mice. Then 1.5 mm³fragments were prepared for s.c. implantation into the animals. The bodyweight of the animals averaged 19±2 g at dose initiation In contrast toExample 1, the animals used were all female. The doses and dosingregimens for each treatment group were similar to those for Example 1,except that MMC was injected on days 1 and 13 after initiation oftreatment on day 0 and the study continued over a 28 day period afterinitiation of treatment.

Results are shown in Table 3 and FIG. 2. Table 3 shows the calculatedmean TVs on day 0 and day 28, as well as the calculated mean RTV, T/C(%) and % Inhibition. The RTV on day 28 (D28) was 12.45±4.46 for theVehicle Control group, 4.97±1.85 for the MMC treated group, 7.42±1.91for the 0.15 mg rSIFN-co-treated group, 6.64±2.04 for the 0.10 mgrSIFN-co-treated group, and 6.64±1.60 for the 0.05 mg rSIFN-co-treatedgroup. The % Inhibition on day 28 was: 60.08% for the MMC treated group,40.40% for the 0.15 mg rSIFN-co-treated group, 46.67% for the 0.10 mgrSIFN-co-treated group, and 46.67% for the 0.05 mg rSIFN-co-treatedgroup. The corresponding T/C (%) for the MMC-treated group, the 0.15 mgrSIFN-co-treated group, 0.10 mg rSIFN-co-treated group, and the 0.05 mgrSIFN-co-treated group were: 39.92%, 59.60%, 53.33% and 53.33%,respectively. The differences in RTV between each of the treated groupsand the Vehicle Control group were determined to be statisticallysignificant. Results showed that rSIFN-co was effective in inhibitinggrowth of human cervical cancer in the test animals.

TABLE 3 Activity of rSIFN-co on Human Cervical Cancer Hela XenograftsTV(mm³, TV(mm³, mean ± SD) mean ± SD) RTV T/C % Treatment (D 0) (D 28)(mean ± SD) (%) Inhibition P value normal saline 138 ± 25 1720 ± 756 12.45 ± 4.46   (12 mice) MMC 130 ± 28 676 ± 358 4.97 ± 1.85** 39.9260.08 p < 0.01 0.15 mg 136 ± 25 1025 ± 400  7.42 ± 1.91*  59.60 40.40 p< 0.05 rSIFN-co 0.10 mg 135 ± 28 865 ± 186 6.64 ± 2.04** 53.33 46.67 p <0.01 rSIFN-co 0.05 mg 135 ± 26 886 ± 232 6.64 ± 1.60** 53.33 46.67 p <0.01 rSIFN-co

FIG. 2 shows the progression of RTV for each treatment group over the28-day study period, reflecting the tumor measurements made on days 4,7, 11, 14, 18, 21, 25 and 28 after the start of treatment. Resultsshowed retardation of human cervical tumor growth in each of theMMC-treated group and rSIFN-co-treated groups by day 7, which wasmaintained until day 28.

All animals in the study tolerated the rSIFN-co treatments with no signsof toxicity. Very little change in average body weight was observed overthe 28-day treatment period.

Example 3. Activity of rSIFN-Co on Human Colon Cancer

This study was conducted to demonstrate the activity and efficacy ofrSIFN-co on treatment of human colon cancer, using a HT-29 as a model.Results showed that rSIFN-co was active and efficacious in inhibitingthe growth of human colon cancer cells. This study was conducted as inExample 1, except as specifically indicated otherwise. Human coloncancer xenografts were first established and prepared in a similarmanner as in Example 1, by inoculating 5×10⁶ HT-29 cells subcutaneouslyinto nude mice and passaging the well-grown xenografts twice in nudemice. Then, 1.5 mm³ fragments were prepared for s.c. implantation intothe test animals. The body weight of the animals averaged 20±2 g at doseinitiation In contrast to Example 1, the animals used in this study wereall female. The doses and dosing regimens for each treatment group areas set forth in Example 1 except that MMC was administered to Group 3 ondays 1 and 10, and an additional group, Group 7, was added in which eachmouse in the group was treated with IFN alpha-2b in a volume of 0.15 mland at a dose of 0.15 mg/mouse, every other day as in therSIFN-co-treated groups, and that treatment was carried out for a totalof 4 weeks. This IFN-alpha-2b, at a concentration of 1.41 mg/ml, wasprovided by Huiyang Life Science and Technology Corp. Results are shownin Table 4 and FIG. 3.

TABLE 4 Activity of rSIFN-co on Human Colon Cancer HT-29 XenograftsTV(mm³, TV(mm³, mean ± SD) mean ± SD) RTV T/C % Treatment (D 0) (D 28)(mean ± SD) (%) Inhibition P value normal saline 131 ± 23 1107 ± 424 8.41 ± 2.82  (12 mice) MMC 132 ± 22 395 ± 95   3.12 ± 1.19*** 37.10 62.9 p < 0.001 (5 mg/kg) rSIFN-co 131 ± 36 570 ± 144 4.51 ± 1.25** 53.6346.37 p < 0.01 0.15 mg rSIFN-co 128 ± 39 541 ± 196 4.22 ± 0.87** 50.1849.82 p < 0.01 0.10 mg rSIFN-co 130 ± 26 416 ± 166  3.28 ± 1.25*** 39 61 p < 0.001 0.05 mg IFNalpha-2b 128 ± 44 831 ± 420 6.26 ± 1.43  74.4425.56 p > 0.05 0.15 mg

Table 4 shows the calculated beginning mean TV on day 0 and the endingmean TV on day 28, as well as the calculated mean RTV, T/C (%) and %Inhibition. The RTV on day 28 (D28) was 8.41±2.82 for the VehicleControl group, 3.12±1.19 for the MMC treated group, 4.51±1.25 for the0.15 mg rSIFN-co-treated group, 4.22±0.87 for the 0.10 mgrSIFN-co-treated group, 3.28±1.25 for the 0.05 mg rSIFN-co-treatedgroup, and 6.26±1.43 for the IFN alpha-2b-treated group. The %Inhibition on day 28 was: 62.9% for the MMC treated group, 46.37% forthe 0.15 mg rSIFN-co-treated group, 49.82% for the 0.10 mgrSIFN-co-treated group, 61% for the 0.05 mg rSIFN-co-treated group, and25.56% for the IFN alpha-2b-treated group. The corresponding T/C (%) forthe MMC-treated group, the 0.15 mg rSIFN-co-treated group, 0.10 mgrSIFN-co-treated group, the 0.05 mg rSIFN-co-treated group, and the IFNalpha2b-treated group were: 37.10%, 53.63%, 50.18%, 39.00% and 74.44%,respectively. Results showed that rSIFN-co was more effective than IFNalpha-2b in inhibiting growth of human colon cancer cells. Thedifferences in RTV between each of the treated groups and the VehicleControl group were determined to be statistically significant.

FIG. 3 shows the inhibition of growth of human colon tumor, asrepresented by RTV for each of the treatment groups over the 28-daystudy period, reflecting the tumor measurements made on days 3, 7, 10,14, 17, 21, 24 and 28, after the start of treatment. Results showedretardation of human colon tumor growth in each of the MMC-treated groupand the rSIFN-co-treated groups by day 7, which was maintained until day28. Each of the 3 doses of rSIFN-co caused more inhibition of tumorgrowth than IFN alpha-2b.

As in Examples 1 and 2, all rSIFN-co-treated animals tolerated thetested dosages and showed no signs of drug toxicity and minimal changesin weight.

Example 4. Activity of rSIFN-Co on Human Lung Cancer

This study was conducted to demonstrate the activity and efficacy ofrSIFN-co on treatment of human lung cancer, using a SPC-A4 as a model.Results showed significant inhibition of human lung tumor growth byrSIFN-co and that rSIFN-co was much more effective than IFN alpha-2b.The study was conducted as in Example 3, except as specificallyindicated otherwise. Human xenografts for injection into the testanimals were first established and prepared in a similar manner as inExample 1, but by inoculating 2.5×10⁶ SPC-A4 cells subcutaneously (s.c.)in nude mice and passaging the well-grown tumors twice in nude mice. The1.5 mm³ fragments were then used for s.c. implantation into the testanimals. The body weight of the animals averaged 22±2 g at doseinitiation. In contrast to Example 3, the animals used in this studywere all male and the study was conducted over a 21 day treatmentperiod. The doses and dosing regimens for each treatment group are asset forth in Example 3 except that MMC was administered to Group 3 ondays 1 and 6. Results are shown in Table 5 and FIG. 4.

TABLE 5 Effect of rSIFN-co on growth of human lung cancer SPC-A4xenografts in nude mice. TV(mm³, TV(mm³, mean ± SD) mean ± SD) RTV T/C %Treatment (D 0) (D 21) (mean ± SD) (%) Inhibition P value normal saline168 ± 42 7133 ± 2708 42.54 ± 2.82   (12 mice) MMC 166 ± 42 1831 ± 540 11.54 ± 4.37*** 27.13 72.87  p < 0.001 (5 mg/kg) rSIFN-co 169 ± 40 2284± 653  13.72 ± 3.96**  32.25 67.75 p < 0.01 0.15 mg rSIFN-co 168 ± 492388 ± 1544 14.91 ± 11.19** 35.05 64.95 p < 0.01 0.10 mg rSIFN-co 170 ±41 2244 ± 1043 15.45 ± 9.07**  36.32 63.68 p < 0.01 0.05 mg IFNalpha-2b191 ± 44 4908 ± 2433 27.84 ± 15.51  65.47 34.53 p > 0.05 0.15 mg

FIG. 4 shows the inhibition of growth of human lung tumor in nude mice,as represented by RTV for each of the treatment groups over the 21-daystudy period, reflecting the tumor measurements made on days 4, 7, 11,14, 18, and 21, after the start of treatment. Results showed retardationof tumor growth in each of the MMC-treated group and rSIFN-co-treatedgroups by day 7, which was maintained until day 21 when the study ended.Tumor inhibition was not seen with the IFN alpha-2b treated group untilday 11. Inhibition of tumor growth by IFN alpha-2b was less than that byany of the rSIFN-co-treated groups and was not statistically significant(p>0.05). Hence, rSIFN-co was more effective in inhibiting growth ofhuman lung cancer cells than IFN alpha-2b.

As in Examples 1-3, all animals tolerated the tested dosages of testarticles and no signs of toxicity or weight loss were observed, exceptthat one mouse in the 0.05 mg rSIFN-co-treated group died on day 17, forreasons unknown.

Example 5. rSIFN-Co Reduced Viability of Various Human Solid CancerCells

Cell culture and reagents. human lung cancer cell lines (A549, H1299,H460, Calu-1), human liver cancer cell lines (SMMC-7721, Huh-7, CL-1),human cervical carcinoma cell line (Hela), human breast cancer cell line(MDA-MB-231), human pancreatic cancer cell line (PANC-1) and human coloncancer cell lines (SW620, HT29, SW480) were purchased from the ShanghaiCell Collection (Shanghai, China). The above cell lines were cultured in5% CO₂ at 37° C. in corresponding complete growth medium formulated bythe Shanghai Cell Collection, with 10% heat-inactivated fetal bovineserum (Biochrom, Germany), supplemented with 4 mM glutamine, 50 U/mlpenicillin and 50 mg/ml streptomycin. The complete growth media were:F-12K (lot #GNM21127; Hangzhou Gino Bio-Medical Technology Ltd.) forA549; L-15 (lot #41300-039, GIBCO) for SW620 and MDA-MB-231; DMEM (lot#C11995, GIBCO) for SMMC-7721, Hela, Huh-7, CL-1, and PANC-1; RMPI-1640(lot #C11875, GIBCO) for H460, H1299, and SW480; Macro5a (lot #M4892,Sigma) for HT-29; and DMEM+10% FBS for Calu-1.

About 5×10³ cells in 100 μl complete medium per well were plated in96-well plates, incubated overnight, and then treated with IFN α-2b orrSIFN-co at concentrations of 100 μg/ml, 50 μg/ml, 25 μg/ml, 12.5 μg/ml,6.25 μg/ml, 3.13 μg/ml, 1.56 μg/ml, 0.78 μg/ml, 0.39 μg/ml, and 0.20μg/ml, respectively, for about 48 hr, at which time the cells wereharvested for analysis. The cell viability rate was evaluated by SunBioAm-Blue assay kit (Cat #: SBAB8025, Shanghai SBO Medical BiotechnologyCo., Ltd, Shanghai, China). According to its protocol, 10 μl Am-Blue wasadded to each well. Then the cells were incubated in 5% CO₂ at 37° C.for 4 hours. After shaking the plates for 30 seconds, the absorbance foreach well was read at both 570 nm and 595 nm by a Thermo ScientificMicroplate Reader (Thermon Fisher Scientific, Inc., Lowell, Mass.). Therelative cell viability was calculated as follows: Cellviability=(Treated Group_((OD570-OD595)) minusBlank_((OD570-OD595)))/(Control group_((OD570-OD595)) minusBlank_((OD570-OD595)))×100%, where the Control group was thecorresponding untreated cells. Results are shown in FIG. 5, in whichviability of the tumor cells was expressed as a percentage relative tocontrol cells that were not treated. Each data point represented themean of at least two independent experiments.

FIG. 5 shows the dose response curve for each cancer cell line, (A)through (I), treated with either rSIFN-co or IFNα-2b in reducing theviability of the cancer cells. (A) A549 cells; (B) Hela cells; (C) CL-1cells; (D) Huh-7 cells; (E) SW480 cells; (F) MDA-MB-231 cells; (G)Calu-1 cells; (H) SMMC-7721 cells; (I) PANC-1 cells.

Results showed that IFNα-2b even at the highest concentration tested(100 μg/ml) had no or very little effect in reducing the viability ofA549 cells, Hela cells, CL-1 cells, SW480 cells, and SMMC-7721 cells.Less than 50% reduction in viability was seen when IFNα-2b at 100 mcg/ml(μg/ml) was used to treat Huh-7 cells, MDA-MB-231 cells, Calu-1 cells,and PANC-1 cells. In contrast, rSIFN-co was able to reduce tumor cellsviability in a dose dependent manner at much lower doses, with close to50% reduction in cell viability at concentrations between 6.25 μg/ml and12.5 μg/ml for SW480 cells, MDA-MB-231 cells, and PANC-1 cells andbetween 12.5 μg/ml and 25 μg/ml for A549 cell, Hela cells, CL-1 cells,Huh-7 cells, Calu-1 cells, and SMMC-7721 cells. Generally, IC₅₀ forrSIFN-co in decreasing cell viability was in a range of about 10 mcg/mlto 18 mcg/ml for different cancer cells. At 100 mcg/ml of rSIFN-co, cellviability could not be detected for any of the cancer cell lines. Thus,rSIFN-co was more effective in reducing tumor cell viability than IFNalpha-2b at each of the concentrations tested.

Example 6A. rSIFN-Co was More Effective in Reducing Cell Viability thanIFN Alpha-2b

To demonstrate the ability of rSIFN-co to reduce cell viability, A549and SW620 tumor cells, each at 2×10³ in 100 μl of complete medium perwell were plated onto 96-well plates, and treated with 10 μg/ml ofrSIFN-co or IFN alpha-2b, respectively, for 1-6 days. The cell survivalrate was evaluated in a standard MTT assay[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,Sigma, St. Louis, Mo.). For the assay, about 20 μl MTT (at 4 mg/ml) wasadded to each well. The cells were incubated at 37° C. for 4 hr. Afterthat, the supernatant of each well was drawn off carefully and then anequal volume (150 microliter) of dimethyl sulfoxide (DMSO) was added toeach well and mixed thoroughly on a shaker for 15 min. The absorbancefrom the plates was read at 595 nm with a Thermo Scientific MicroplateReader (Thermo Fisher Scientific Inc., Lowell, Mass.). The relative cellviability was calculated as follows: Cell viability=(Treatedgroup_((OD595)) minus blank_((OD595)))/(Control group_((OD595)) minusblank_((OD595)))×100%.

Results are expressed as a percentage relative to untreated controlcells. Each data point represents the mean of at least two (2)independent experiments. As shown in FIG. 6, rSIFN-co strongly decreasedcell viability of SW620 cells in a time-dependent manner in contrast toIFN alpha-2b, which had little time-dependent effect, if any. The timedependent effect of rSIFN-co was also apparent for A549 cells for onlyabout the first 3 days of treatment. The difference in effect betweenrSIFN-co and IFN alpha-2b at each time point for each cell line wasstatistically significant (p<0.01). These data showed a stronganti-tumor effect of rSIFN-co in a time-dependent manner.

Example 6B. rSIFN-Co Inhibited Tumor Growth In Vivo

This experiment was conducted in accordance to the National Institutesof Health Guide for the Care and Use of Laboratory Animals. FemaleBALB/c nude mice, 4-5 weeks old, were obtained from ShanghaiExperimental Animal Center (Shanghai, China). About 5×10⁶ A549 cellswere subcutaneously injected into each mouse to establish xenografttumors. The animals were divided into three (3) groups at random (8 miceper group), and treated with PBS (1×PBS, pH 7.2-7.4), rSIFN-co at 100μg/100 μl per mouse or with IFNα-2b, also at 100 μg/100 μl per mouse,intratumorally, every other day, for 12 times. The tumors were measuredevery three (3) days and the tumor volumes were calculated as follows:tumor volume (mm³)=(length×width²)/2. The results are shown in FIG. 16.Data are shown as Mean±SD (n=8). Results demonstrate that rSIFN-co couldalmost completely inhibit growth of established tumors as compared tothe PBS-treated group (p<0.0001). However, IFNα-2b did not exhibitremarkable suppression of tumor growth. Results indicated that rSIFN-cowas more effective than IFNα-2b in inhibiting tumor growth in vivo.

Example 6C. rSIFN-Co Inhibited Colony Formation and Invasive FeetFormation (Pseudopod Formation) by Tumor Cells in Three DimensionalCulture Systems

Matrigel (from BD Corporation, Cat #: 356234) was thawed on ice in a 4°C. refrigerator overnight, and a 24-well plate was frozen at −20° C.overnight. Thereafter, each well of the frozen 24-well plate was coatedwith 150 μl of the Matrigel at 1.0 mg/ml. The Matrigel coated plate wasthen incubated 37° C. for 20-30 min. Lung cancer cells, A549, weretrypsinized and counted. About 5×10³ cells in conditioned mediumcontaining 2% Matrigel, and either 10 mcg/ml of IFN alpha-2b orrSIFN-co, or with no interferons as control were seeded on the Matrigelcoated wells. The cells were incubated at 37° C. for at least about 8days. About 200 μl of the above conditioned medium was added every 3days to prevent the medium from drying. On the 4^(th) or 8^(th) day,photographs were taken to observe the size of the colonies and invasivefeet (pseudopod) formation. The experiment was conducted in triplicate.

Results are shown in FIG. 7. After 4 days, rSIFN-co treated group (FIG.7C) was found to have the smaller colonies than the untreated group(FIG. 7A). After 8 days, the rSIFN-co-treated group not only had thesmallest colonies of the 3 groups, it was found that there was almost noextrusive pseudopodium around the cells (FIG. 7C, rows 2 and 3), whilepeduopod formation was obvious in the cells of the untreated group (FIG.7A, rows 2 and 3) and the IFN alpha-2b treated group (FIG. 7B, rows 2and 3). This experiment shows that rSIFN-co not only could suppress thegrowth of cancer cell colony, but also could inhibit invasive feetformation in the cancer cells, a feature that is necessary formetastasis.

Example 7. Inhibition of Beta-Catenin/TCF Transcriptional Activity byrSIFN-Co

Beta-Catenin/TCF Transcription Reporter Assay.

The effect of rSIFN-co on Wnt/Beta-catenin signaling in vitro wasdetermined. Cancer cells were plated in 96-well plates (at 1×10⁴ cellsper well), and incubated for 12 hours, after which they were transientlytransfected with 100 ng TOPFlash (Millipore Corporation, Billerica,Mass., USA). To normalize transfection efficiency, cells wereco-transfected with 1 ng of internal control reporter Renilla reniformisluciferase driven under the SV40 promoter, pRL-SV40 (Promega, Madison,Wis., USA), and then treated with 10 mcg/ml interferons, rSIFN-co or IFNalpha-2b, or left untreated as Control (Mock) after transfection for 6hours. After interferon treatment for 24 hours, luciferase assay wasperformed using the Dual Luciferase Assay System kit according to themanufacturer's protocols (Cat #:E1960, Promega). Relative luciferaseactivity was reported as a ratio of firefly/renilla luciferase activity.Experiments were performed in triplicate.

Results, shown in FIG. 8, indicated that rSIFN-co decreasedbeta-catenin/TCF mediated transcriptional activity in human solid cancercells. After treatment for 24 hours, the beta-catenin/TCF-mediatedtranscriptional activity was significantly suppressed by rSIFN-co inthree lung cancer cells (A549, H1299, H460) and two colon cancer cells(HT-29, SW620) (*, p<0.05, **, p<0.01). However, the inhibitory effectof IFN alpha-2b was non-existent for A549 cells, H1299 cells, H460 cellsand HT-29 cells and had resulted in enhancement, instead of inhibition.

Briefly, the Firefly/Renilla ratios for the Control group, the IFNalpha-2b-treated group and the rSIFN-co-treated groups were,respectively: (A) for the A549 cells: about 310, about 350, and about100; (B) for the H1299 cells: about 800, about 1000, and about 500; (C)for the H460 cells: about 450, about 500, and about 280; (D) for theHT-29 cells: about 300, about 600, and about 200; (E) for the SW620cells: about 1500, about 1200, and about less than 100. This study showsthat rSIFN-co was superior to IFNα-2b in the suppression of Wnt/TCFsignaling and hence, in its antitumor effect.

Example 8. rSIFN-Co Decreased Beta-Catenin Protein Level in Cancer Cells

Cancer cells, A549 and Sw480, were cultured to about 85% confluency andput into 6 well plates. The cells were treated with either 10 mcg/mlIFNα-2b or rSIFN-co or left untreated as control (Mock) for 24 hr, 48hr, or 72 hr, respectively. After treatment, the cells were harvestedfor Western Blot to detect the beta-catenin protein level, using itsspecific antibody, with GAPDH as endogenous loading control. Theexperiment was conducted in triplicate.

Western Blot Analysis.

To determine the expression of various proteins, cells were harvestedfrom the plates and total cellular protein were extracted usingextraction reagents (Cat #: P0013) according to the manufacturer'sprotocol (Beyotime, China). The total protein concentration wasdetermined by the Lowry Protein Assay kit (Bio-Rad, USA). Total proteinswere separated by sodium dodecylsulfate-polyacrylamide gelelectrophoresis (SDS-PAGE) on 10%-12% gel and transferred to 0.22 or0.45 μm PVDF membranes (Millipore Corporation, Billerica, Mass., USA).The membranes were blocked with 5% skimmed milk, bovine serum albumin,10 mmol/L Tris-HCl at pH 8.0, 150 mmol/L NaCl, and 0.05% Tween 20overnight at 4° C. The blocked membranes were then incubated withprimary antibodies (1:1000 dilutions), followed by secondaryHRP-conjugated antibodies. Blots were visualized usingLuminescence/Fluorescence Imaging LAS4000 System (GE Healthcare LifeSciences, USA) with super signal west pico chemiluminescent substratekit (Thermo scientific, USA).

For this determination, the primary antibodies used were mousemonoclonal anti-beta-catenin antibodies (1:1000; Santa Cruz Technology,Santa Cruz, Calif.) and mouse monoclonal anti-GAPDH antibodies (1:2000)(Kangwei Biotechnology, China). Anti-mouse HRP-conjugated secondaryantibodies (Santa Cruz Technology, Santa Cruz, Calif.) were used atconcentrations of 1:2000. Results, shown in FIG. 10, demonstrate that asfor A549 cells, rSIFN-co dramatically decreased beta-catenin proteinlevel after treatment for 2 days (48 hr). Further decrease was observed,for these cells, after treatment for 3 days (72 hr). Decrease inbeta-catenin protein level in the SW480 cells was obvious after 72 hoursof treatment with rSIFN-co. Down-regulation of beta-catenin wasapparently time dependent in both the lung cancer A549 cells and thecolon cancer SW480 cells. In contrast, IFN alpha-2b did not cause anyapparent decrease in beta-catenin level, suggesting that it had noeffect on the down-regulation of beta-catenin.

Example 9. rSIFN-Co Induced Transcriptional Down-Regulation of WntPathway Mediated Target Genes

The lung cancer A549 cells were seeded into 6-well plates and treatedwith 10 μg/ml of either IFN alpha-2b or rSIFN-co, respectively, or wereleft untreated as control (Mock). After 24 hr of treatment, cellulartotal mRNA was isolated using TRIZOL Reagent and cDNA was synthesizedand further subjected to qPCR, using specific primers of four (4) Wntsignaling downstream genes, Axin2, CD24, Survivin and ID2. Experimentswere conducted in triplicate and normalized with the Mock group.

Quantitative PCR (qPCR) Analysis.

Total mRNA was isolated using TRIZOL Reagent (Invitrogen, Carlsbad,Calif.) according to the manufacturer's instructions. Complementary DNA(cDNA) was synthesized using a RT-PCR Kit (Cat #:FSQ-101, TOYOBO, Japan)according to the manufacturer's instructions and then subjected to qPCRwith a SYBR Green PCR kit (Cat #: QPK-201, TOYOBO, Japan). The primersof the four Wnt pathway target genes were as follows: Axin2 senseprimer: 5′-CGTGGATACCTTAGACTT-3′ (SEQ ID NO:8) and antisense primer:5′-GCTGTTGTTCTCAATGTA-3′(SEQ ID NO: 9); CD24 sense primer:5′-TGAAGAACATGTGAGAGGTTTGAC-3′ (SEQ ID NO: 10) and antisense primer:5′-GAAAACTGAATCTCCATTCCACAA-3′(SEQ ID NO: 11); Survivin sense primer:5′-ACCGCATCTCTACATTCAAG-3′ (SEQ ID NO: 12) and antisense primer:5′-CAAGTCTGGCTCGTTCTC-3′ (SEQ ID NO: 13) and ID2 sense primer:5′-CACAACAACAACAACAAC-3′ (SEQ ID NO: 14) and antisense primer:5′-CACAGTCCAAGTAAGAGA-3′(SEQ ID NO: 15).

The amplification protocol consisted of incubations at 95° C. for 1minute, 40 cycles (95° C. for 15 seconds, 60° C. for 15 seconds, 72° C.for 30 seconds). Incorporation of the SYBR Green dye into PCR productswas monitored in real time with a Bio-Rad Detection System andsubsequently analyzed using Bio-Rad CFX manager 2.1 software. Thesamples were pooled for each condition and run in duplicate. Treatedsamples were compared to Mock using the 2^(−ΔΔ)Ct method and plotted asfold change. GAPDH was used as the normalization control.

Results, shown in FIG. 11, demonstrate that rSIFN-co induceddown-regulation of Wnt pathway mediated target genes, Axin2, CD24,survivin, and ID2. The mRNA level of these genes were significantlyreduced after rSIFN-co treatment but not after interferon IFN alpha-2btreatment.

Briefly, when the relative expression level for the Mock control was setat 1, for the Axin2 gene (FIG. 11A), the IFN alpha-2b treatment resultedin a level of slightly over 1, while rSIFN-co treatment resulted in alevel of about 0.4 (p<0.0001, comparing rSIFN-co treatment with notreatment). The corresponding levels for the CD24 gene (FIG. 11B) were1, about 0.9 and about 0.4 (p<0.0001), respectively; for the Survivingene (FIG. 11C) were 1, about 0.9, and about 0.4 (p<0.0005),respectively; for the ID2 (FIG. 11D) gene were 1, about 1, and about 0.4(p<0.0001), respectively, for Mock untreated cells, IFNalpha-2b-treatedcells and the rSIFN-co-treated cells, respectively.

Example 10. rSIFN-Co could Down-Regulate Wnt-Related Receptors orCo-Receptors LRP6/FZD6 mRNA Level in Different Cells

The regulation of LRP6/FZD6 by rSIFN-co was investigated. This wasconducted by qPCR as performed in Example 9. Cancer cells, A549, H460,SW620 and HT-29, were seeded into 6-well plates and treated with 10μg/ml IFN alpha-2b or rSIFN-co or was left untreated as control (Mock).After 24 hr of treatment, total cellular mRNA was isolated using TRIZOLReagent, and cDNA was subjected to qPCR using specific primers of LRP6and FZD6. The primers used were: LRP6 sense primer:5′-TGAAGAACCAGCACCACAGG-3′ (SEQ ID NO: 4) and antisense primer:5′-CATAACCAAGAGGCACAGAAGC-3′ (SEQ ID NO: 5), and FZD6 sense primer:5′-GCGGAGTGAAGGAAGGATTAGTC-3′ (SEQ ID NO: 6) and antisense primer:5′-TGAACAAGCAGAGATGTGGAACC-3′ (SEQ ID NO: 7). Experiments were conductedin triplicate and normalized with the Mock control group. Results wererecorded as relative mRNA level of either LRP6 or FZD6 relative toGAPDH.

Results, shown in FIG. 9, indicated that both LRP6 and FZD6 weredown-regulated to various extents by rSIFN-co in the four cancer celllines. FIG. 9A shows significant reduction in the relative expression ofthe LRP6 mRNA in the A549 cells (p<0.005), SW620 cells (p<0.005) and theHT-29 cells (p<0.005) after rSIFN-co treatment but no significantreduction was seen with the IFN alpha-2b treatment. FIG. 9B showssignificant reduction in relative expression of FZD6 mRNA in all 4 celllines, A549 (p<0.001), H460 (p<0.0005), SW620 (p<0.001), and HT-29(p<0.0005) after treatment with rSIFN-co. The other interferon, IFNalpha-2b caused enhancement of FZD6 mRNA expression in HT-29 cells, butinduced some reduction in FZD6 mRNA expression, though not to the sameextent as rSIFN-co, in A549 cells, H460 cells and SW620 cells. Resultsindicate that the suppression of Wnt signaling pathway by rSIFN-co mighthave resulted from the inhibition of expression of the Wnt relatedcellular surface receptors LRP6 and FZD6. rSIFN-co was found to besuperior to interferon IFNα-2b in suppressing the Wnt pathway, in thehuman cancer cells tested, such as human lung cancer and human coloncancer cells, including the down-regulation of beta-catenin/TCF-mediatedtranscriptional activity and beta-catenin protein level, as well as Wntsignaling pathway related receptors, co-receptors and target genes.

Example 11. rSIFN-Co Up-Regulated the Expression of Tumor SuppressorGenes

The effect of rSIFN-co on the up-regulation of tumor suppressor geneswas demonstrated in this study. Cancer cells, A549, H460, SW620 andHT-29, were seeded into 6-well plates and treated with 10 mcg/ml of IFNalpha-2b or rSIFN-co, or were left untreated as Mock control. After 24hr of treatment, total cellular mRNA was isolated using TRIZOL Reagent,and cDNA was synthesized, and further subjected to qPRC using specificprimers for DKK3, KLF4 and BATF2. The following primers were used: forBATF2, sense primers: 5′-CAGAGCAGGGAGCACAAACC-3′ (SEQ ID NO: 16) andantisense primers: 5′-TGAGCAGAGGAGAGCAGAGG-3′ (SEQ ID NO: 17); for DKK3,sense primers: 5′-GGAGCCTGACTGAAGAGATGG-3′(SEQ ID NO: 18) and antisenseprimers: 5′-ACGCCTAAAGCACACACCTG-3′ (SEQ ID NO: 19); for KLF4, senseprimers: 5′-CCTTCAACCTGGCGGACATCAAC-3′ (SEQ ID NO: 20) and antisenseprimers: 5′-GGCTGCTGCGGCGGAATG-3′ (SEQ ID NO: 21).

The experiment was conducted in triplicate and normalized with the mockcontrol group. Results, shown in FIG. 12, were expressed as relativemRNA expression level in relation to that of GAPDH. For the A549 cells,treatment with rSIFN-co dramatically increased the expression of all 3tumor suppressor genes, DKK-3 (FIG. 12A), BATF2 (FIG. 12B), and KLF4(FIG. 12C) and was much more effective than IFN alpha-2b. In SW620cells, up-regulation of KLF4 expression after rSIFN-co treatment wasalso dramatically increased as compared to control and IFN alpha-2btreatment. IFN alpha-2b treatment dramatically enhanced DKK-3 expressionin H460 cells.

Example 12. rSIFN-Co Inhibited Cancer Cell Migration

The ability of rSIFN-co to suppress tumor cell migration wasdemonstrated by determining the ability of lung cancer A549 cells andcolon cancer SW620 cells to migrate across microporous membranes aftertreatment with IFN alpha-2b or rSIFN-co for 24 hr, as compared tountreated control (Mock). The cell migration assay was performed using 8μm cell culture inserts in 24-well plates (Becton-Dickinson Biosciences,NJ, USA). Warm (37° C.) bicarbonate based culture medium without FBS wasadded to the interior of the inserts and to the bottoms of the wells,and were allowed to rehydrate for 2 hr in humidified tissue cultureincubator at 37° C. in 5% CO₂. After rehydration, the culture medium wascarefully removed. Subsequently, the 500 μl of prepared cells (aftertreatment with either 10 μg/ml of IFN alpha-2b or 10 μg/ml of rSIFN-co,or not having been treated at all) suspended in FBS-free medium wereseeded onto the upper part of the insert filters at a density of 0.5×10⁴cells/insert. In the lower compartment of the 24-well plates were placed500 μl of complete medium with 10% FBS. After 24 hr at 37° C. under theregular culture conditions, the non-migrated cells in the upper part ofthe chamber membranes were removed with a cotton swab. The lower part ofthe culture inserts were fixed with 4% paraformaldehyde and stained with2% crystal violet. The number of migrated cells on the opposite side ofthe chamber membranes from where the cells were placed was counted ineach of the triplicate wells. Each experiment was repeated at least twotimes, each time with triplicate wells.

Results, shown in FIG. 13, showed the mean number of migrating cells perfield for each of the Mock, IFN alpha-2b-treated cells, andrSIFN-co-treated cells. For the A549 cells that had migrated across themembrane, about 30 cells per field were observed in the untreated Mockgroup, about 110 cells were seen in the IFN alpha-2b group, and about 10cells were seen in the rSIFN-co-treated group. The enhancement ofmigration caused by IFN alpha-2b treatment and the inhibition ofmigration caused by the rSIFN-co treatment were statisticallysignificant (p<0.01). Significant inhibition by rSIFN-co was alsoobserved with SW620 cells. In contrast, IFN alpha-2b treatment resultedin enhancement of tumor cell migration in SW620 cells. Hence, rSIFN-cowas effective inhibiting tumor cell migration, and was much moreeffective than IFN alpha-2b.

Example 13. rSIFN-Co Did not Exert its Effect Through the ApopotosisPathway

This study was performed to show that rSIFN-co exerted its effect onreducing the viability of tumor cells by other than the apoptoticpathway. Tumor cells, A549 and SW620, were plated into 6-well plates,incubated overnight and then treated with either 10 mcg/ml of IFNalpha-2b, or 10 mcg/ml of rSIFN-co or with 5FU or were left untreated(as Mock control) for 24 hr or 48 hr. Thereafter, apoptosis-relatedmolecular markers were monitored by Western Blot. The primary antibodiesused were mouse monoclonal anti-beta-tubulin (1:2000, Cat #: CW0098A)and mouse monoclonal anti-GAPDH (1:2000, Cat #: CW0100A) (KangweiBiotechnology, China); mouse monoclonal anti-PARP (1:1000, Cat #:sc-2007, Santa Cruz Biotechnology, Inc.); rabbit monoclonalanti-procaspase 3 (1:1000, Cat #: 9665), and rabbit polyclonalanti-cleaved caspase 3 (1:1000, Cat #: 9661) (Cell Signaling Technology,USA); goat polyclonal anti-procaspase 8 (1:1000, Cat #: sc-6136, SantaCruz Biotechnology, Inc); rabbit monoclonal anti-cleaved caspase 8(1:1000, Cat #: 9496) (Cell Signaling Technology, USA).

Results are shown in FIG. 14A, for A549 cells and FIG. 14B for SW620cells. The Western Blots showed that after treatment with 5FU, a drugknown to cause apoptosis, the cells exhibited a significant reduction ofin the level of procaspase-3, procaspase-8 and PARP, but exhibited anenhanced level of cleaved caspase-3 and cleaved caspase-8. In contrast,neither of the interferons, IFN alpha-2b nor rSIFN-co, caused anyreduction in the level of procaspase-3 or procaspase-8 or PARP, orinduced any enhancement in the level of cleaved caspase-3 or cleavedcaspase-8. Thus, results indicated that the two interferons, especiallyrSIFN-co, likely caused reduction in tumor cell viability by a differentmechanism than through apoptosis.

Example 14. rSIFN-Co Induced STAT Phosphorylation

This experiment was conducted to show that rSIFN-co utilized theJAK/STAT signaling pathway just as IFN alpha-2b. In this study, A549cells and Hela cells were each plated into 3.3 cm dishes, incubated at37° C. overnight, and then treated with 10 μg/ml of either IFN alpha-2bor rSIFN-co for 0, 5, 15, 30, 60, 120 and 240 minutes respectively.After treatment, the cells were collected, cellular proteins wereextracted and loaded onto SDS-PAGE agarose for Western Blot analysis toobserve the phosphorylation of STAT1 (Tyr701), STAT2 (Tyr690), andSTAT3(Tyr705). GAPDH was used as a loading control.

The primary antibodies used were: STAT1 (1:1000, Cat #: 9175S), Tyr701phosphorylated-STAT1 (1:1000, Cat #: 9167S), STAT2 (1:500, Cat #4594),Tyr690 phosphorylated-STAT2 (1:1000, Cat #: 441S), STAT3 (1:1000, Cat #:9132), Tyr705 phosphorylated-STAT3 (1:1000, Cat #: 9145S). Anti-mouse(Cat #:sc-2005) or rabbit (Cat #: sc-2004) or goat (Cat #: sc-2020)HRP-conjugated secondary antibodies (Santa Cruz Technology, Santa Cruz,Calif.) were used at concentrations of 1:2000. Blots were visualized byuse of Luminescence/Fluorescence Imaging LAS4000 System (GE HealthcareLife Sciences, USA) with super signal west pico chemiluminescnetsubstrate kit (Thermo Scientific, USA).

Results, shown in FIG. 15, demonstrate that the 2 interferons, IFNalpha-2b and rSIFN-co behaved similarly in their phosphorylationpatterns for STAT1, STAT2 and STAT3 in both A549 cells and Hela cells.Hence, rSIFN-co-mediated JAK/STATs signaling level was no different fromthat mediated by IFN alpha-2b, suggesting that rSIFN-co and IFN alpha-2bmay share the common IFNAR1/2 receptors.

Example 15. The Affinity Binding of rSIFN-Co to IFNAR1 and IFNAR2

Binding affinities of both IFNα-2b and rSIFN-co toward IFNAR1-EC (Cata:13222-H08H, Sino Biological Inc) or IFNAR2-EC (Cata: 10359-HO8H, SinoBiological Inc) were measured using the Biacore T100 Protein InteractionArray system (General Electric HealthCare Co.), based on surface plasmonresonance technology. For immobilization of the receptor subunit, a CM5sensor chip was incubated with the IFNAR1-EC subunit and IFNAR2-ECsubunit, at 20 μg/ml and 50 jag/ml, respectively, binding thecarboxylated dextran surface of the chip via their amino groups inproteins. The two tested interferons were then injected perpendicular toligands at different concentrations within a range of 100-3,000 nM forIFNα-2b/IFNAR1 binding and 50-1,000 nM for rSIFN-co/IFNAR1 binding aswell as another range of 3.125-80 nM for both of them on IFNAR2 binding,which was added with regenerated 2 M NaCl buffer for 5 secondsreactivated procedure during IFNs/IFNAR2 binding. Data were analyzedaccording to the manufacture's protocol. Dissociation constants K_(D)were determined from the rate constants according to the Equation,K_(D)=kd/ka (d: dissociation; a: association).

FIG. 17, shows the different receptor binding affinity of rSIFN-co andIFNα-2b. Under the conditions of this experiment, affinity constant ofIFNAR1 interferon receptor can be analyzed by steady-analysis model:K_(D) (IFNAR1-EC/_rSIFN-co): 6.003×10⁻⁷ mol/L; K_(D)(IFNAR1-EC/IFNα-2b):2.835×10⁻⁶ mol/L (FIG. 17A); Affinity constant of IFNAR2 interferonreceptor can be analyzed by dynamic-analysis model: K_(D)(IFNAR2-EC/rSIFN-co): 2.192×10⁻⁸ mol/L; K_(D) (IFNAR2-EC/IFNα-2b)1.843×10⁻⁹ mol/L (FIG. 17B); With regard to comparison on their affinityconstants, rSIFN-co/IFNAR1 exerts stronger binding affinity (4.72 times)when it was compared to interferon IFNα-2b (FIG. 17C). The bindingaffinity of rSIFN-co/IFNAR2, however, demonstrated 11.9 times weakerthan that of IFNα-2b (FIG. 17C).

Example 16. rSIFN-Co Induced Higher p-STATs than IFNα-2b after B18RPre-Treatment in Cancer Cells

In this study, A549 and Hela cells were cultured for overnightincubation. 10-fold serial dilutions (1, 10 and 100 ng/ml, final assayconcentrations) of B18R recombinant protein (Vaccinia virus-EncodedNeutralizing Type I Interferon Receptor, also called type I IFNinhibitor, Catalog number: 14-8185, eBioscience, Inc) were prepared inmedia and combined with a constant amount (1 ng/ml, final assayconcentration) of each IFN protein (IFNα-2b and rSIFN-co) for 1 h atroom temperature. The B18R/IFN complexes were used to treat the abovetwo cells and incubated for 30 min. Then, the cellular lysate iscollected to detect the phosphorylation of STAT1 (Tyr701), STAT2(Tyr690), and STAT3 (Tyr705) by western blot assay. GAPDH and Actin wereused as a loading control.

The primary antibodies used were: STAT1 (1:1000, Cat #: 9175S) (CellSignaling Technology, USA), Tyr701 phosphorylated-STAT1 (1:1000, Cat #:9167S) (Cell Signaling Technology, USA), STAT2 (1:500-1:1000, Cat #4594)(Cell Signaling Technology, USA), Tyr690 phosphorylated-STAT2(1:500-1:1000, Cat #: 441S) (Cell Signaling Technology, USA), STAT3(1:1000, Cat #: 9132) (Cell Signaling Technology, USA), Tyr705phosphorylated-STAT3 (1:1000, Cat #: 9145S) (Cell Signaling Technology,USA), GAPDH (Cat #: CW0100A, Kangwei biotech, Inc), b-actin (Cat #:CW0096, Kangwei biotech, Inc).

FIG. 18 shows rSIFN-co showed greater induction of phosphorylation onSTAT1/2/3 at 10 ng/ml of inhibitor B18R in A549 cells (FIG. 18A) andHela cells (FIG. 18B) as compared to the IFNα-2b group.

INDUSTRIAL APPLICABILITY

The methods and assay kits described herein are useful for determiningthe potency of a test compound, such as an interferon, and for treatmentof certain diseases or conditions which are negatively affected byover-activity or over-expression of beta-catenin, or any one or more ofLRP6, FZD6, Axin2, CD24, Survivin, and ID2 or by down-regulation ofDKK3, BATF2 or KLF4.

What is claimed:
 1. A method of determining or comparing potency of atest interferon relative to Recombinant Super-Compound Interferon(rSIFN-co), or establishing substantial equivalence between a testinterferon and rSIFN-co, comprising the steps of: (1) providing a firstsample, a second sample and a third sample of cancer cells of the sametype; (2) treating the first sample with the test interferon, treatingthe second sample with rSIFN-co, and using the third sample as a controlsample; and (3) measuring binding affinity of said test interferon andrSIFN-co to Interferon Alpha And Beta Receptor Subunit 1 (IFNAR1) andInterferon Alpha And Beta Receptor Subunit 2 (IFNAR2) in the first,second and third samples; wherein similar binding affinity to IFNAR1between the first and second samples, and similar binding affinity toIFNAR2 between the first and second sample indicates substantialequivalence between the test interferon and the rSIFN-co.
 2. The methodof claim 1, wherein the cancer cells comprise any one or more of: lungcancer cells, colon cancer cells, cervical cancer cells, liver cancercells, breast cancer cells, and pancreatic cancer cells.
 3. The methodof claim 1, wherein the cancer cells comprise HT-29 cells.
 4. The methodof claim 1, wherein the test interferon has about 2, 3, 4, or 4.5 timeshigher binding affinity to IFNAR1 as compared to the third samplecontaining IFNα-2b.
 5. The method of claim 1, wherein the testinterferon has about 5, 7, 9, or 11 times lower binding affinity toIFNAR2 as compared to the third sample containing IFNα-2b.
 6. The methodof claim 1, wherein the binding affinity to IFNAR1 or IFNAR2 isdetermined by dissociation constant (K_(D)).
 7. The method of claim 1,wherein the test interferon has an amino acid sequence that is at least90% identical to SEQ ID NO:
 1. 8. The method of claim 1, wherein thetest interferon is encoded by a nucleotide sequence that is at least 90%identical to SEQ ID NO:
 2. 9. The method of claim 1, wherein the testinterferon and rSIFN-co have the same amino acid sequence of SEQ ID NO:1, and are encoded by the same nucleotide sequence of SEQ ID NO:
 2. 10.The method of claim 1, wherein the test interferon and rSIFN-co havesubstantially the same specific activity.
 11. The method of claim 10,wherein the specific activity is in the range between about 4×10⁸ IU/mgand about 1×10⁹ IU/mg.